Influence of seed-borne endophytic bacteria and their consortia from the invasive Lactuca serriola on soil phosphorus availability and plant competitive ability

Tae-Min Kim 광주과학기술원 공과대학 2026 국내박사

Seed-borne endophytes represent vertically transmitted microbial assemblages that can influence early plant development and adaptation to nutrient stress. Despite their ecological relevance, their roles in regulating soil nutrient dynamics and plant competitiveness remain underexplored, particularly in invasive species. This dissertation investigates the contributions of seed endophytic bacteria associated with the invasive plant Lactuca serriola L., focusing on their ability to mobilize soil phosphorus (P) under deficiency and to mediate soil–plant interactions across ecological contexts. By integrating trait-based screening, in planta validation, and competition experiments, this study provides a mechanistic framework linking microbial inheritance with invasion-related nutrient cycling. Nineteen representative bacterial isolates were obtained from surface-sterilized seeds of wild L. serriola and characterized for key plant growth-promoting (PGP) traits, including indole-3-acetic acid (IAA) production, phosphate-solubilizing activity (PSA), siderophore production (SPP), and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. All isolates exhibited at least one PGP trait, and consortium-level assembly revealed emergent interactions beyond single-strain performance. In particular, consortia containing Kosakonia cowanii SD1 and Xanthomonas spp. SD2 displayed strong synergistic enhancement of phosphate solubilization, indicating functional complementarity among seed-derived strains. Under phosphate-deficient conditions, dual-strain inoculations constructed around K. cowanii SD1 or Xanthomonas spp. SD2 significantly increased soil available phosphorus relative to single and uninoculated controls. The consortia of K. cowanii SD1 with Pantoea dispersa SD25 and Xanthomonas spp. SD2 with Stenotrophomonas maltophilia SD8 showed the highest soil available phosphorus. These findings demonstrate that cooperative metabolism among vertically inherited endophytes can enhance soil P mobilization under strong nutrient limitation. However, these soil-level improvements were not consistently accompanied by increased plant biomass or leaf P concentration, suggesting a decoupling between microbial nutrient transformation and immediate host benefit. In competition experiments under varying phosphate conditions, bacterial inoculation consistently elevated soil available phosphorus across monoculture and interspecific settings, yet plant responses remained limited and varied across phosphate and competition conditions. Endophyte-mediated nutrient mobilization thus functioned more as an environmental modifier than a direct growth promoter, subtly altering soil nutrient balance rather than competitive hierarchies. Collectively, these findings reveal that seed-borne bacterial consortia in L. serriola act as inherited nutrient regulators capable of altering soil phosphorus dynamics through cooperative metabolism. Such vertically transmitted consortia represent a heritable microbial mechanism that enhances environmental adaptability and may contribute to the persistence of invasive plants in nutrient-impoverished habitats. This study advances an integrative perspective linking microbial inheritance, synergism of endophytes, and ecological outcomes, thereby expanding the conceptual scope of invasion ecology to include inherited microbial processes driving nutrient cycling.

Molecular mechanism of seed triacylglycerol biosynthesis by multiple transcription factors in plants

김인영 세종대학교 대학원 2024 국내박사

Plant seed oil is primarily accumulated in the form of triacylglycerols (TAGs), which is composed of three fatty acids esterified to glycerol during seed development. It serves as an energy source for seed germination and seedling initial growth. The seed oil is utilized in various industries, including food, detergents, lubricants, paints, and biodiesel. Fatty acid and triacylglycerol biosynthesis involves a series of reactions catalyzed by numerous enzymes. During seed development, master regulators such as LEAFY COTYLEDON 1 (LEC1), LEC2, ABSCISIC ACID INSENSITIVE 3 (ABI3), and FUSCA 3 (FUS3) control downstream transcription factors (TFs) and fatty acid synthesis genes for lipid accumulation. Among these, the LEC2 transcription factor is a key regulator of triacylglycerol biosynthesis by activating the transcription factor WRINKLED1 (WRI1). However, further research is needed to understand the mechanisms by which LEC2 regulates lipid synthesis through other downstream transcription factors besides WRI1. Therefore, this study identified five transcription factors regulated by LEC2 and investigated how the WRKY8 and DPBF2 transcription factors regulate lipid synthesis during seed development. This study revealed that LEC2 regulates the WRKY8 expression by activation of the WRKY8 promoter. WRKY8 localizes to the nucleus and expressed in the embryos during seed development. A mutation of WRKY8 in Arabidopsis using CRISPR/Cas9 gene editing technology was reduced seed TAG contents along with shorter silique length and reduced seed yield compared to the wild type (WT). The seed-specific overexpression of WRKY8 in Arabidopsis (WRKY8-OE) slightly increased seed size and weight, but decreased seed TAG contents and significantly altered fatty acid composition. Their fatty acid composition showed an increase in 16:0, 18:0, and 18:2 fatty acids, and a decrease in 18:1, 18:3, and 20:1 fatty acids compared to the WT. During the seed oil accumulation, WRKY8 upregulated the fatty acid synthesis genes FAD2 and PDCT and transcription factors LEC1/2 and L1L, while downregulating KASII, FAB2, FATA/B, FAD3, FAE1, and the transcription factors ABI3, FUS3, and DPBF2. This pattern corresponded with the changes in fatty acid composition of the WRKY8-OE lines. Additionally, WRKY8 directly regulated the expression of FAD2 and PDCT through their promoter activation. The WRKY8-OE lines inhibited seed germination compared to the wild type, with a more sensitive the hormone abscisic acid (ABA). These results demonstrate that WRKY8 plays a role in transcriptional regulation of fatty acid biosynthesis genes in seeds. Furthermore, the function of WRKY8 is conserved in the camelina oil crops. Next, DPBF2 is a seed-specific transcription factor that upregulated by LEC2 and localized to the nucleus. Both the dpbf2-1 T-DNA insertion mutant and seed-specific DPBF2 overexpression using the phaseolin promoter exhibited similar seed fatty acid compositions. Compared to the WT, they increased 18:2 and 20:1 fatty acids and decreased 18:1 and 18:3 fatty acids. The expression of fatty acid biosynthesis genes including FAD2/3, LPCAT1/2, PDCT, and FAE1 were upregulated by DPBF2. Specifically, DPBF2 with the L1L and NF-YC2 transcription factors, positively regulated PDCT and FAE1. These findings indicate that the DPBF2 transcription factor is involved in the synthesis of unsaturated fatty acids in seeds by regulating the expression of various fatty acid synthesis genes. This study contributes to our understanding of the molecular mechanisms and complex transcriptional regulatory networks for seed oil synthesis. These findings can be utilized to regulate the synthesis of specific unsaturated fatty acids.

Endozoochorous seed dispersal by Korean water deer (Hydropotes inermis argyropus)

이승경 서울대학교 대학원 2021 국내박사

Seed dispersal is an important ecological process that affect vegetation structure. Long-distance seed dispersal (>100 m) maintains plant community connectivity and genetic diversity, and enables plants to adapt to changing environments, such as habitat fragmentation and climate warming. Seed dispersal by ingestion and defecation by animals (i.e., endozoochory) can spread seeds over long distances. In particular, ungulates—given their large home range and long gut retention time—are important long-distance seed dispersal vectors in terrestrial ecosystems. The potential and success of seed dispersal is determined by various factors; however, how regional flora and consequent diet choice affect endozoochory is not well understood. Moreover, there are conflicting results from studies of the effects of gut passage on seed recovery and germination rate. Therefore, the goal of this thesis was to investigate the effect of habitat flora and diet choice on endozoochory potential as well as the effects of gut passage on seed recovery and germination. The ungulate studied is the Korean water deer (Hydropotes inermis argyropus), the most dominant wild ungulate in South Korea. The study was conducted in the lowland and forest area, which are representative habitats of the deer. Firstly, through germination tests using feces, the endozoochory potential of the deer with respect to different habitats, seasonal changes, and plant traits was assessed and compared with the local flora. Secondly, the differences in diet according to habitat, season, and feeding type were investigated by conducting a diet analysis using fecal DNA barcoding. Finally, through feeding experiment and germination tests, the effects of gut passage on seed recovery and germination rate were evaluated. As a result of the germination test of fecal samples, in both habitats, Chenopodium album and Portulaca oleracea were predominant, and the number of species and seeds were higher in lowland area compared to forested area. Irrespective of the local flora, the seeds that were dispersed mainly by endozoochory by Korean water deer were of the following types: seeds with a length of less than 2 mm, seeds with growth form of forbs, seeds from open areas, and seeds without special morphology of seed dispersal. The results of the diet analysis using DNA barcoding showed that the composition of diet differed by habitat and season. The amount of woody plant consumption was greater in the forested area, and the amount of forbs and graminoids was greater in the lowland area. The overall feeding type of the deer was concentrate feeder, mainly feeding on woody plants. As a result of the feeding experiments, six out of eight species fed to the deer were recovered as intact seeds. The recovery rate was different for each species, and most of the seeds were recovered between 24 and 48 hours after feeding. The effect of intestinal passage on seed germination differed according to species. Overall, seed recovery and germination rate decreased after the gut passage. In conclusion, most of the plant species dispersed by Korean water deer endozoochory are forbs and graminoids, and more number of species and seeds were found in lowland area. As greater amount of forbs and graminoids consumption in lowland area may have resulted the differences. The diet choice of forbs and graminoids, which can be dispersed by endozoochory may have been reflected in the amount of seeds dispersed by endozoochory. However, by dispersing seeds with similar plant traits regardless of flora, Korean water deer can act as an indirect ecological filter in the region by endozoochory. Additionally, although endozoochory by Korean water deer seems to have high costs of low seed recovery and germination rate, the seeds can be potentially dispersed over long distances. The results of this study are expected to contribute to a comprehensive understanding of the mechanism of long-distance seed dispersal by ungulates. 종자 산포는 식생 구조에 영향을 미치는 중요한 생태학적 과정이다. 장거리 종자 산포(>100 m)는 식물 군집의 연결성, 유전적 다양성을 유지시키며 서식지 단편화, 기후온난화 등 변화하는 환경에 있어 식물을 적응 할 수 있게 한다. 동물에 의한 섭취 및 배변에 의한 종자 산포인 체내 식물종자 산포는 장거리로 종자를 분산시킬 수 있다. 특히, 유제류는 행동 반경이 크고, 소화시간이 길어 육상 생태계 내에서 중요한 장거리 종자산포원이다. 종자 산포의 잠재성 및 성공은 다양한 요소에 의해 결정되는데, 서식지의 식물상과 이에 따른 산포원의 먹이 선택이 복합적으로 미치는 영향에 대해서는 잘 알려져 있지 않다. 또한, 산포동물의 소화기관이 종자의 회수 및 발아율에 미치는 영향은 연구마다 다른 결과를 나타낸다. 이에 본 연구에서는 우리나라에서 흔하게 나타나는 유제류 야생동물인 한국 고라니(Hydropotes inermis argyropus)를 대상으로 서식지의 식물상과 먹이 선택이 체내 식물종자 산포에 미치는 영향과 고라니의 소화기관이 종자 회수 및 발아에 미치는 영향에 대해 연구를 실시하였다. 고라니의 대표적인 서식지인 저지대와 산림 지역에서 연구를 진행하였다. 첫째, 각 서식지의 체내 식물종자 산포 잠재성, 계절적 변화 및 식물의 특성을 분변을 이용한 발아 실험을 통하여 확인하였고 이를 지역의 식물상과 비교하였다. 둘째, 서식지와 계절에 따른 먹이 선택의 차이 및 먹이 유형을 분변 DNA바코딩을 이용한 먹이 분석을 실시하여 알아보았다. 마지막으로, 고라니의 소화기관이 종자의 회수 및 발아에 미치는 영향에 대해 고라니 먹이 실험 및 발아 실험을 통하여 연구하였다. 분변 발아 실험 결과, 두 서식지 모두 우점종은 명아주, 쇠비름으로 확인되었으며, 저지대에서는 산포되는 종자의 종수 및 유묘수 모두 계절적인 변화가 나타났으나, 산림지역에서는 계절적인 변화가 나타나지 않았다. 산포되는 종수 및 유묘수 또한 산림 지역에 비하여 저지대에서 많았다. 고라니에 의한 체내 식물종자 산포는 두 지역 모두 2 mm이하 길이를 갖는 종자, 광엽 초본 생장형을 가지는 종자, 개활지 서식지의 종자, 특별한 종자분산형태를 갖지 않은 종자를 주로 산포하는 것으로 나타났다. 이는 지역의 식물상과 관련이 없었다. DNA바코딩을 이용한 먹이 분석 결과, 알파다양성은 크게 다르지 않았으나, 종 조성에 해당되는 베타다양성은 서식지별로, 계절별로 다르게 나타났다. 고라니의 먹이 유형은 목본 식물을 주로 먹는 집중형 채식자로 나타났으며, 산림 지역의 경우 목본 식물의 비율이 높고, 저지대의 경우 광엽 초본과 화본형 식물의 비율이 높은 것을 확인하였다. 먹이 실험 결과, 고라니에게 먹인 8종 중 6종이 온전한 종자로 회수되었으며 회수율은 종별로 달랐으며, 대부분의 종자가 먹인 후 24시간에서 48시간 사이에 회수되었다. 장 통과가 종자 발아에 미치는 영향은 종별로 달랐으며 전반적으로 종자 회수율 및 발아율은 감소하는 것으로 나타났다. 종합하자면, 고라니의 소화기관을 거쳐 산포되는 식물종의 대부분은 광엽 초본형 또는 화본형 식물이었으며 산림 지역에 비하여 저지대에서 보다 많은 수의 종과 유묘를 확인하였다. 이는 저지대가 산림 지역에 비하여 광엽 초본형과 화본형 식물을 일부 먹이로 하는 것이 원인으로 추정된다. 즉, 서식지의 식물상의 차이에 따른 체내 식물종자 산포 잠재성을 가지는 식물에 대한 먹이 선택의 차이가 체내 식물종자 산포로 산포되는 종자의 양으로 반영됨음을 시사하고 있다. 그러나 체내 식물종자 산포로 식물상과 관련없이, 유사한 식물 특성을 가지는 종자를 산포하여 고라니에 의한 체내 식물종자 산포가 간접적인 생태학적 필터로 작용할 수 있다고 판단된다. 또한, 고라니에 의한 체내 식물종자 산포는 비록 낮은 종자 회수율과 발아율을 갖지만 식물종자를 장거리로 산포하는 이점을 가질 것으로 생각된다. 본 연구결과는 유제류에 의한 장거리 종자산포 기작의 종합적인 이해에 기여할 것으로 판단된다.

Enhancing Seed Production of Regionally Adapted Crops in the Southeastern Farmer Seed System

Davidson, Maria Teresa University of Florida ProQuest Dissertations & The 2023 해외박사(DDOD)

Seed production is an essential agricultural practice for seed security, crop production, and restoration of native species. However, in many regions, smallholder farmers rely on unorganized, informal seed systems that limit options for seed availability. The lack of information and technology available to farmers within informal seed systems can lead to poor-quality seeds due to non-optimal harvest and storage practices that reduce yield and seed viability. Variable climatic factors represent another challenge posed to seed production. I aimed to identify seed developmental markers that help characterize the best harvest times to obtain high-quality seeds.Moreover, I determined influential factors affecting the intention of southeastern U.S. farmers to adopt seed production practices. I found that 'Mississippi Purple' (Vigna unguiculata L.) seeds reach mass maturity by 35 DAA, and the study of aging under stress demonstrated high seed vigor. I concluded that producing high-quality cowpea seeds is possible in regions such as north central Florida. Two main aspects resulted from studying 'Butterfly milkweed' (Asclepias tuberosa L.) grown in on-farm conditions for seed production. First, recent transplants may require two years of acclimatization to overcome transplant stress and produce seeds of acceptable quality. Second, seeds stored in a climate-controlled room (i.e., 23 to 26°C; 45 to 50% Relative Humidity RH) may be exposed to aging stress that reduces seed viability. I was able to demonstrate that 50 DAA is the minimum time to harvest 'Bellevue Butternut' (Cucurbita moschata) seeds since germination performance improved greatly by this time. Nonetheless, moisture content, water potential, and chlorophyll levels continue to decrease, suggesting that seeds may require longer periods of time to complete with the developmental program. Yet, seed vigor essay indicated that seeds at 50 DAA are highly tolerant to stressful conditions. Seed production of 'Yukina Savoy' (Brassica rapa L.) with high-quality and vigor is also achievable in hot and humid conditions. Results displayed that after 45 DAA seeds can be harvested although at 55 DAA seeds reached lower moisture and water potential levels. In both, 45 and 55 DAA, seed vigor was high as only after 125 days of exposure to stress seeds started to show deterioration, demonstrating a great capacity to tolerate stress and storage conditions. One of the main aspects learned in this study with 'Yukina Savoy' was that seeds may acquire dormancy at harvest. The results of the social study generated two constructs: perceived benefits and perceived challenges of engaging in seed production. The salient perceived benefits are locally and regionally adapted seeds, reliable seed availability, and independence from external suppliers. The salient perceived challenges are a lack of knowledge, skills, and training in seed production, financial constraints, and adverse climatic conditions. Data shows that farmers producing seeds intend to continue the practice. Still, about half of the non-seed producers participating in the study are not. Education about biology and technology related to seed production may motivate engaging in the practice.

A Study on the Genes Related with Seed Dormancy in Arabidopsis thaliana

김아진 서울대학교 대학원 2018 국내석사

Seed dormancy is a phenomenon that seed postpones its growth until environment is suitable for its survival. Some genetic or environmental factors that affect seed dormancy have been identified but the mechanism of controlling seed dormancy is still elusive. Recently, some epigenetic regulators of seed dormancy have been reported. AtJmj4, a gene encoding H3K4 demethylase in Arabidopsis, is expressed highly in seed of freshly-harvested (FH) state which possesses the highest seed dormancy level. This suggests that AtJmj4 might play a role in the regulation of seed dormancy. Meanwhile, OsSDR4 is well known as a seed dormancy regulator in rice. Several homologs of OsSDR4 in Arabidopsis have been discovered depending on their amino acid sequence homologies; AtSDR4 is the closest homolog of OsSDR4. The lack of AtSDR4 caused enhanced seed dormancy, which is the opposite phenotype of ossdr4 mutation, which causes a reduced seed dormancy. The function of other homologs, AtSDR4H1 and AtSDR4H2, in seed dormancy has also not been reported. In this study, AtJmj4 and AtSDR4 were investigated at the aspect of seed dormancy regulation. The atjmj4-1 mutation did not alter the seed dormancy phenotype in wild-type (WT) Columbia (Col) background or ColDOG1_Cvi backgrounds at 22 ℃. However, atjmj4-1 seeds showed reduced dormancy than WT seeds at 12 ℃. In the dormancy test using atsdr4-1, atsdr4h1-1, atsdr4h2-1, and their multiple mutants, it was suggested that atsdr4-1 but not atsdr4h1-1 or atsdr4h2-1 mutation enhances the seed dormancy. Gene expression analysis revealed that the genes involved in ABA synthesis and signaling, as well as DOG1, the representative seed dormancy regulator, are upregulated in atsdr4-1 FH seeds than in WT seeds. To test if any phenotypes related to germination also exist, red light-dependent germination tests were performed and none of atjmj4-1, atsdr4-1, atsdr4h1-1 and atsdr4h2-1 showed substantially altered germination phenotypes, although atsdr4-1 showed retarded radicle-emergence phenotype. Germination tests with exogenously supplied ABA suggested that the slow radicle extrusion phenotype of atsdr4-1 is probably due to the ABA hypersensitivity. Overall, these results indicate that AtJmj4 is a minor positive regulator of seed dormancy at low temperature and AtSDR4 is a major negative regulator of seed dormancy.

Seed transmission of Tomato yellow leaf curl virus in tomatoes

김선후 성균관대학교 일반대학원 2015 국내석사

Tomato yellow leaf curl virus (TYLCV) is one of the tomato-infecting begomoviruses transmitted by sweet potato whitefly Bemisia tabaci. Seed transmission has been reported from some plant viruses, but no geminivirus was confirmed as a seed-borne virus from any study. In 2013 and 2014, TYLCV was identified from young tomato plants germinated from fallen tomatoes cultivated in the previous cultivating season. Additionally, TYLCV was also detected from floral tissues and seeds of naturally infected and artificially inoculated tomato plants and seedlings of their offspring. Same viral sequences were identified from seeds and seedling of offspring from agro-inoculated tomato plants. Commercial seeds of cultivar ‘A’ and their seedlings were confirmed as TYLCV-infected and sequences of seeds and seedlings showed high similarity to sequence of TYLCV isolates from seed collection country (Japan). TYLCV-infected seeds were also confirmed to serve as an inoculum source of TYLCV in vector-meditated transmission. This is the first report on seed transmission for TYLCV in tomato.

Seed-Mediated Growth of Graphene Nanoribbons on Germanium Via Chemical Vapor Deposition

Way, Austin ProQuest Dissertations & Theses The University of 2020 해외박사(DDOD)

Graphene nanoribbons possess exceptional electrical and thermal properties, among other unique qualities, which makes them a material of interest for next-generation electronics such as high-frequency communication devices, logic circuits, optoelectronics, photonics, and sensors. Unlike graphene, which is a semimetal, graphene nanoribbons can be semiconducting when they possess a width <10 nm. However, the difficulty of synthesizing ribbons with the qualities required for device applications has remained a challenge.Ribbons must have sub-10 nm widths, lengths greater than 100 nm, controlled orientation and placement, and a smooth, armchair edge structure for reliable integration in semiconductor electronics. Additionally, the synthesis must be scalable and on a technologically relevant substrate. While many fabrication techniques exist, none have been able to achieve all of the necessary characteristics.In this work, we develop novel nanoribbon fabrication routes to address these challenges and advance our knowledge of graphene synthesis on Ge(001) via chemical vapor deposition. We explore the concept of seeding nanoribbon growth through integration of lithographically patterned graphene seeds, delve into the interactions of graphene seeds with the Ge surface and adjacent seeds, and advance the approach through the use of monodisperse small molecule seeds.We find that the use of graphene seeds provides control over where crystal growth occurs, allows crystal orientations that are unobserved naturally on Ge(001), and decouples the effects of nucleation and growth. We discover that the angle between armchair orientation of lithographically patterned graphene seeds with the Ge⟨110⟩ family of directions dictates the resulting nanoribbon’s orientation and anisotropy. By aligning these directions, the growth anisotropy is maximized and high-aspect ratio nanoribbons result; however, when the directions are misaligned, a low aspect ratio crystal occurs. Utilizing this knowledge, we construct a plot analogous to a Kinetic Wulff plot that predicts the shape and anisotropy of the graphene crystal growth on Ge(001). By manipulating the seeds favorably, we fabricate unidirectional arrays of graphene nanoribbons with precise placement and greatly reduced polydispersity in the length and width, as compared to non-seeded ribbon growth. This work provides a framework toward the fabrication of wafer-scale arrays of semiconducting, armchair graphene nanoribbons with controlled placement and orientation with potential application in a variety of semiconductor technologies.Through improvement of our seed-initiated synthesis process, we garner greater understanding of the graphene nanoribbon growth regime and the influence of pitch (seed to seed distance) and seed size on nanoribbon characteristics. Experimental results show that growth kinetics are invariant to pitches as low as 50 nm and in conjunction with computational modeling, indicate that the kinetics are either strongly attachment limited or the diffusion length of the growth species is ≪ 50 nm. Additionally, periodic arrays of nanoribbons are successfully fabricated from graphene seeds with sub-5 nm diameters, resulting in sub-10 nm nanoribbon widths. This advancement enables nanoribbons with sub-10 nm widths to be fabricated with pitches lower than 50 nm, promising improved integration in hybrid integrated circuits.We also report our discovery of seed rotation on Ge(001) as a function of seed diameter and orientation. While previous results demonstrated that misaligned seeds result in low aspect ratio crystals, we find that high aspect ratio ribbons can result if the seed diameter is small enough. A critical seed diameter of 18 nm is determined for seed rotation to occur. We determine that seeds preferentially rotate to the nearest Ge direction. Utilizing this knowledge, nanoribbon meshes with sub-10 nm widths are fabricated. These results suggest the potential to created meshes, interconnects, and other unique architectures for various device applications.Utilizing the knowledge of our previous seeding work, we report the successful growth of graphene nanoribbons via molecular seeds. Through manipulation of the growth conditions, nanoribbons narrower than 5nm, and as low as 2.5 nm, are synthesized on Ge(001). The nanoribbons possess long segments of armchair edges and demonstrate a nearly 3 times improvement on width polydispersity, as compared to non-seeded nanoribbon synthesis. Leveraging this uniformity control, nanoribbons with 3.5 and 6.1 nm widths are produced and integrated into field effect transistors, which demonstrate an on/off ratio thatdiffers by 2 order of magnitude due to the difference in width. This groundbreaking work opens the door for extensive experimental studies on the impact of molecular seed type, the potential of molecular seeds as dopants, the origin and nature of nanoribbon growth on Ge(001), as well as potential application on other two-dimensional materials.

매자나무과의 종자 및 종피 해부형태

김용우 강원대학교 대학원 2019 국내석사

매자나무과 15속 24종에 대하여 종자 해부형태를 조사하였다. 그 결과, 열매는 장과(berry), 골돌과(follicle), 수과(achene), glandispermidium으로 분류되었다. 종피 해부형태의 분석에서는 종피의 목질화, 미분화형, 섬유상 발달, 방사상구조 등의 특징이 유용한 식별형질로 판단되었다. 매자나무과의 종피유형은 Nandina속을 제외하고 모두 외종피외층형(exotestal type)이며, Nandina속의 종피형태는 과내에서 유일한 내종피내층형(endotegmic type)으로 여전히 매자나무과 내에서 독특한 특징을 나타내었다. 국내에서 한계령풀과 혼동하는 Gymnospermium속은 Leonticeae족 내에서 유일하게 종자 부속물(aril)이 존재하였다. 따라서 종자 부속물이 존재하지 않는 한계령풀은 Leontice속으로 분류하는 것이 보다 정확한 분류체계로 판단되었다. 또한, Bongardia, Caulophyllum, Gymnospermium, Leontice속과 같은 열매(infructescence)는 glandispermidium으로 분류하여야 한다. Berberis, Mahonia, Ranzania속은 염색체 수(X=7) 및 분자학적 데이터에서 높은 유연관계를 보여주었으며, 실제로 종피구조에서도 외종피외층(exotesta)이 목질화하여 발달하는 공통적인 특징을 보여주었다. Epimedium, Jeffersonia속의 종자 부속물은 배주의 주병(funicle)에서 유래되는 종의(aril)로 관찰되었다. Bongardia속은 종피구조로 볼 때, 외종피외층(exotesta)이 섬유상으로 신장되는 두꺼운 후벽세포로 발달한다는 점에서 Epimedium속과 매우 유사한 구조를 나타내었다. Podophyllmum속은 횡단면과 종단면 모두에서 외종피외층(exotesta)이 목질화 된 두꺼운 후벽세포로 발달하여 배와 배유를 보호하였다. 또한, 외종피외층(exotesta)이 과내의 다른 속들 보다 상당히 두꺼운 후벽세포층을 나타내었다. Diphylleia속의 종피구조는 외종피외층(exotesta)이 장방형의 목질화하는 후벽세포층으로 발달하였으며, Podophyllum속의 종피구조와 유사하였다. 또한, Dysosma속의 종피구조는 외종피외층(exotesta)에서 cuticle층이 발달하는 것을 관찰 할 수 있었으며, Diphylleia속과 Podophyllum속의 중간형질 정도로 판단되었다. Achlys속의 종피구조는 외종피외층형 이지만 횡단면과 종단면에서 얇은 후벽세포층만 관찰되었으며 뚜렷한 특징이 관찰되지 않았다. Achlys속의 종피구조와 분류학적 위치에 관한 연구는 좀 더 필요한 것으로 생각되며, Gymnospermium속의 종자부속물 발달 위치에 대한 명확한 연구가 필요하다고 사료된다. Seed anatomy of Berberidaceae of 24 different genera was investigated in this study. Based on the results, fruits were classified as berry, follicle, achene, and glandispermium. For the morphological and anatomical characters of seed coat such as lignification, undifferentiation, fibrous development and radial structure were determined as identification and useful traits. Seed coat type of Berberidaceae is exotestal type whereas endotegmic type in endoplasmic reticulum for the Nandina. Since Gymnospermium, which is confused with a ‘Han Gye Ryung’ in Korea, is the only seed appendage in the tribe Leonticeae. It was confirmed to be accurate to classify without seed appendage as Leontice. In addition, infructscence such as Bongardia, Caulophyllum, Gymnospermium and Leontice should be classified as glandispermidium. Genus Berberis, Mahonia and Ranzania showed close affinity in the chromosome number (X = 7) and molecular data, and showed a common characteristic that the exotesta in the seed coat structure developed by lignification. Seed attachments of the Jeffersonia and Epimedium were observed as arils originating from the funicular of ovule, instead of the caruncle where the outer integument of the ovule developed abnormally. The genus Bongardia showed very similar structure to that of Epimedium in that the exotesta developed into fibrous-shaped thick wall cells. All of the genus Podophyllum developed in the transverse and longitudinal sections of the exotesta to thick sclerenchyma cell and protected the seeds. In addition, the exotesta showed a much thicker sclerenchyma cell layer than the other genus in the Berberidaceae. The morphological structure of Diphylleia was developed as sclerenchyma cell layer with exotesta of rectangular shape and it was confirmed to have a structure similar to that of Podophyllum. The developed of the cuticle layer in the exotesta of Dysosma was observed to be intermediate between Diphylleia and Podophyllum. Although the seed coat structure of the Achlys was an exotestal type, only a thin cell layer was observed in the transverse section and the longitudinal section, and no distinct features were observed. Studies on the structure and taxonomic position of Achlys is needed more, and it is necessary to clarify the developmental position of seed attachment in Gymnospermium.

Environmental Stability and Genetic Study for Seed Starch Content in Soybean : 콩 종자의 전분 함량에 대한 환경 안정성 및 유전 연구

둥가나산지브쿠마르 경북대학교 대학원 2017 국내박사

Seed starch content (SSC) greatly affects the taste, flavor, and processing properties of soy foods. Soybeans having different seed compositions are suitable for preparing various kinds of soy foods. Food-type soybeans are either consumed directly or further processed to prepare soy foods. Five soybean genotypes (2 cultivars, 2 mutant lines, and one breeding line) were used in the present study to investigate the variation in seed composition during soybean development and maturation. Significant variations in genotype, day after flowering (DAF), and their interaction were observed for SSC and crude fat (CF), whereas the variations were not significant for crude protein (CP) content. The two mutant lines showed lower variation (6.13-7.66%) in SSC than the other three genotypes (9.08-9.97%) from 30 to 70 DAF. Plant breeders consider the interaction between genotype and environment results for the recognition of performance of genotypes of the desired quality when evaluated in different locations. Genotypes showing a high degree of genotype × environment (G×E) interaction are considered unstable across sites. The G×E interaction and stability of SSC in 19 soybean genotypes were investigated in the present study. Nineteen genotypes were cultivated on two planting dates at three locations over two years (2015 and 2016). The G×E interactions were highly significant (P < 0.0001) for SSC, CF, and CP. The average SSC content was higher in 2015 than that in 2016. Late planted soybean showed higher SSC than in early planted ones. The SSC content was found negatively affected by higher average temperatures and longer cloudiness during pod-filling stage. Significant negative correlations between SSC and CP as well as CP and CF contents were found. However, the positive correlation between SSC and oil content was not significant (P = 0.0714). An understanding of genetic basis of SSC is crucial in order to develop and improve the starch content in soybean seeds. In the present study, a total of 169 recombinant inbred line (RIL) population derived from an interspecific cross of Williams 82 and PI 366121 were grown for three consecutive years (2013, 2014, and 2015) and utilized to assess the phenotypic variation (PVE) for SSC. The parents and RILs exhibited significant variation for the SSC. The SSC of the RIL displayed continuous variation with transgressive segregation and hence amenable for QTL mapping. A total of nine significant QTL distributed on 5 different chromosomes were identified. The PVE displayed by the QTL ranged 5.6-11.3%. The QTL qSTR06_2 showed highest PVE (9.1-11.3%) at logarithm of odds (LOD) values of 4.25-5.38. No stable QTL over three years were identified, indicating strong environmental influence on SSC. However, the QTL qSTR06_2, flanked by the markers BARC-062515-17881 and BARC-0010777-00746, was identified in 2013 and 2015 as well as in the combined data of three years. The QTL qSTR11_01 and qSTR20_1 were found to colocalize with some of the previously reported QTL for sucrose content in soybean, implying the interrelationship between starch and sucrose biosynthesis. Positive as well as negative additives effects were displayed by the identified QTL, suggesting contribution of favorable alleles from both the parents. Since the starch content may affect key constituents like oil and protein in soybean seed, findings of the present study could be useful in breeding and selecting soybeans with improved seed composition. 종자 전분 함량 (SSC)은 콩 식품의 맛, 향 및 가공 특성에 크게 영향을 미친다. 다양한 종자 조성을 갖는 대두는 다양한 종류의 콩 식품을 제조하기에 적합하다. 식용 콩은 직접 또는 가공 식품으로 제조하여 소비한다. 본 연구에서는 대두 발육 및 성숙 과정에서 종자 조성의 변화를 조사하기 위해 5 가지 대두 유전자형 (2개 품종, 2개 변종, 1개 계통)을 사용 하였다. 콩의 유전자형, 개화 후 일수 (DAF)에 따른 SSC와 조지방 (CF) 함량은 유의한 차이를 보였고 이들 상호 작용 또한 유의 한 차이가 관찰 되었으나, 조단백질 (CP) 함량에 대해서는 유의성이 인정되지 않았다. 개화 후 30-70일 사이에 SSC함량은 2개의 돌연변이 계통이 6.13-7.66%로 다른 3개 유전자형 (9.08-9.97 %)보다 변이가 적게 나타났다. 식물 육종가는 다른 지역에서 콩 유전자형의 품질을 평가할 때 유전자형과 환경 간의 상호 작용을 고려한다. 본 연구에서는 19종의 대두 유전자형을 사용하여 SSC에 대한 G × E 상호 작용과 안정성을 조사 하였다. 콩 재배는 2년에 걸쳐 3곳에서 2회 파종시기를 달리하여 파종하였다. SSC, CF, CP에 대한 G × E 상호 작용 매우 유의한 결과를 보였다 (P <0.0001). 평균 SSC는 2016년 보다 2015년에 높게 측정되었다. 재배시기에 따른 SSC는 일찍 파종하는 것 보다 늦게 파종하는 것이 높게 나타났다. 꼬투리 성숙단계의 SSC는 평균 기온이 높고 날씨가 흐려질수록 부정적으로 영향을 받는 것으로 나타났습니다. CP와 CF 함량 간에는 유의적인 부의 상관관계가 있었으며, SSC와 CP 함량 간에도 동일한 유의적인 부의 상관관계를 나타내었다. 그러나 SSC와 지방 함량 간에는 유의한 양의 상관 관계가 인정되지 않았다 (P = 0.0714). 대두 종자의 전분 함량을 향상시키기 위해서는 SSC의 유전적 기초를 이해하는 것이 중요하다. 이 연구에서는 Williams 82와 PI 366121 간의 교배에서 얻은 총 169개의 RIL 개체를 3년 (2013, 2014, 2015) 연속 재배하여 SSC의 변이를 평가하는데 이용하였다. 양친과 RIL 개체군의 SSC는 변이의 폭이 크게 나타났다. RIL의 SSC는 초월분리의 연속적인 변이를 나타내었고, 이것은 QTL mapping 작업에 적합하였다. 5개의 다른 염색체에 분포 된 총 9 개의 중요한 QTL을 확인하였으며, PVE는 5.6-11.3% 범위였다. QTL qSTR06_2는 4.25-5.38의 logarithm of odds (LOD) 값에서 가장 높은 PVE 값(9.1-11.3%)을 보였다. 시험 수행 3년 동안 안정적인 QTL이 확인되지 않아 SSC에 대한 환경 적 영향이 강하다는 것을 알 수 있었다. 그러나 BTL-062515-17881 및 BARC-0010777-00746 marker가 붙은 QTL qSTR06_2는 2013년과 2015년 데이터뿐만 아니라 3년간의 통합 데이터에서도 확인되었다. QTL qSTR11_01과 qSTR20_1은 이전에 보고 된 콩의 자당 QTL과 일부 공존하는 것으로 밝혀졌는데, 이것은 자당과 전분의 생합성이 상호 관련성이 있다는 것을 의미하는 것으로 사료된다. 본 연구 결과는 콩 전분 함량이 콩 종자의 기름이나 단백질과 같은 주요 성분에 영향을 줄 수 있으므로 종자의 구성성분이 개선 된 대두를 육종하고 선발하는 데 유용 하게 이용할 수 있을 것으로 사료된다.

Identification and Classification of Seed Coat Sculptures using Deep Learning

간툴가 아리운자야 창원대학교 2023 국내석사

In this study, we worked on the rarest biological data analysis. This research aimed to compare between the human-based classification and machine-based classification. Most common biological data analysis of the work is the identification of plant diseases. The main contribution of this work was to study the suitable use of human-based methods by applying machine-based methods to automatic classification of Allium seed walls (anticlinal and periclinal). Thus, we briefly explain two methods of work. Seed coat characteristics provide important information in the taxonomy of Allium. The seed coat surface was more diverse. In this work, we explored new classification for Allium seed coats, using five different networks CNN, AlexNet, GoogleNet, ResNet50, and VGG16 on Scanning Electron Microscopy (SEM) images over 100 species of Allium seeds. We considered seven common types of anticlinal wall, classified as irregular curved, irregular curved to nearly straight, straight, S, U, UO, and omega. Also, five custom types of periclinal wall distinguished at granule, small verruca, large verruca, marginal verruca, verrucate verrucae. GoogleNet achieved the highest classification accuracy, with 90.4% for the anticlinal wall, and VGG16 achieved the highest accuracy, with 98.1% for the periclinal wall. Therefore, we implemented model performance in more than three, four, and five methods. As a result of the study, more than three methods are more benefit able from more than four and five methods. The implemented models achieved an anticlinal wall classification suitable rate in GoogleNet architecture, and the periclinal wall classification high accuracy rate is VGG16 architecture. In conclusion, using our own machine-based method, we studied the seed coat of species of Allium on our own samples to see if the results of the machine-based method with the human-based match. Seed coat sculptures, including anticlinal and periclinal walls, are great taxonomic importance. In this study, we identified seed coat patterns of Allium seeds using five deep learning methods namely, CNN, AlexNet, GoogleNet, ResNet50, and VGG16 for the first time. Selected images of seed coat patterns from over 100 Allium species reported in previously published literature and data from our samples were classified into seven types of anticlinal (irregular curved, irregular curved to nearly straight, straight, S, U, UO, and omega) and five types of periclinal walls (granule, small verruca, large verruca, marginal verruca, and verrucate verruca). The results revealed that GoogleNet and VGG16 achieved the highest classification accuracy of 90.4% for the anticlinal wall, and VGG16 achieved the highest classification accuracy of 98.1% for the periclinal wall. Moreover, more than three, four, and five methods were combined, and their performance was investigated. Combining more than three methods was the most advantageous. The models achieved a suitable anticlinal wall classification using GoogleNet and periclinal wall classification using VGG16. In conclusion, using the machine-based method, we studied the seed coat of species of Allium on our own samples to see if the results of the machine-based method with the human-based classification match.