Discussion on the Problem of Salt Gland of Glycine soja

Glycine soja Sieb. et Zucc. plants living in saline soil in three provinces of China were treated with different salinity concentrations under different laboratory culture conditions (including solution, sand and field cultivation). The attachment shape and distribution on the surface of stalk and leaf of G. soja plants were observed with scanning electron microscopy (SEM), and the ultrastructure of glandular hair with transmission electron microscopy (TEM). Na+ and Cl- contents in the secretion of the leaf surface and inside the leaf of G. soja subjected to different treatments were measured. The Na+ relative contents in glandular cells, epidermal cells and mesophyllous cells of leaves under different salinities were determined by X-ray microanalysis. Results show that only glandular and epidermal hair exist on the surface attachments of leaves and stalks of G. soja plants. These glandular hair were similar in shape to some salt glands of Gramineae halophytes, and they attached to the vein on the leaf surface. The cell structure of the glandular hair showed the characteristics of common salt glands, such as big vacuoles, dense cytoplasm, a great deal of mitochondria, chloroplast, plasmodesmata and thicker cell walls, etc. The results of Na+ and Cl- contents in the leaf secretion and inside the leaf showed that the glandular hair executed the function of salt-secretion, and when treated with the salt gland inhibitor the salt-secretion process was inhibited. As a result, Na+ and Cl- were mainly accumulated inside G. soja leaves. The results of Na+ X-ray microanalysis under different salinities proved that the three cells of the glandular hair, especially the top cell, possessed strong competence for Na+ accumulation. Above all, the glandular hair were the salt gland, and no other kind of salt glands were found on G. soja plants. The secreting mechanism of the salt gland was also discussed.

Cloning of GsTPS9 Gene from Glycine soja and Study on Its Responses to Stresses

Trehalose synthase is an important functional enzyme in the synthesis of trehalose in organisms and also participates in plant stress-resistant physiological processes.The transcriptomic study showed that a trehalose-6-phosphate synthase gene was responsive to salt and alkaline stresses in Glycine soja.To dissect the molecular mechanisms of this enzyme in plant responses to stresses,the PCR technique was used to clone a trehalose-6-phosphate synthase gene from Glycine soja and it was designated as the GsTPS9.The full-length cDNA of this gene was 2583bp which encoded 861 amino acids.The sequence and structure analyses indicated that the GsTPS9 had high homology with Glycine max GmTPS9.The qRT-PCR analysis revealed that the GsTPS9 gene was expressed in Glycine soja roots,stems and leaves,and the highest expression level was in roots;the GsTPS9 gene had different responses under the stresses of NaCl,NaHCO_(3),PEG6000,ABA,MeJA and SA.This study laid the foundation for revealing the mechanism of the TPS in plant signal transduction pathways.

Constitutive Overexpression of Myo-inositol-1-Phosphate Synthase Gene (GsMIPS2) from Glycine soja Confers Enhanced Salt Tolerance at Various Growth Stages in Arabidopsis

The enzyme myo-inositol-1-phosphate synthase（MIPS EC 5.5.1.4） catalyzes the first step of myo-inositol biosynthesis, a product that plays crucial roles in plants as an osmoprotectant, transduction molecule, cell wall constituent and production of stress related molecule. Previous reports highlighted an important role of MIPS family genes in abiotic stresses particularly under salt stress tolerance in several plant species; however, little is known about the cellular and physiological functions of MIPS2 genes under abiotic conditions. In this study, a novel salt stress responsive gene designated Gs MIPS2 from wild soybean Glycine soja 07256 was functionally characterized contained an open reading frame（ORF） of 1 533 bp coding a peptide sequence of 510 amino acids along with mass of 56 445 ku. Multiple sequence alignment analysis revealed its 92%-99% similarity with other MIPS family members in legume proteins. Quantitative real-time PCR results demonstrated that Gs MIPS2 was induced by salt stress and expressed in roots of soybean. The positive function of Gs MIPS2 under salt response at different growth stages of transgenic Arabidopsis was also elucidated. The results showed that Gs MIPS2 transgenic lines displayed increased tolerance as compared to WT and atmips2 mutant lines under salt stress. Furthermore, the expression levels of some salt stress responsive marker genes, including KIN1, RD29 A, RD29 B, P5 Cs and COR47 were significantly up-regulated in Gs MIPS2 overexpression lines than wild type and atmips2 mutant. Collectively, these results suggested that Gs MIPS2 gene was a positive regulator of plant tolerance to salt stress. This was the first report to demonstrate that overexpression of Gs MIPS2 gene from wild soybean improved salt tolerance in transgenic Arabidopsis.

Cloning and Analysis of Genes SAMS From Glycine soja

S-adenosylmethionine （SAM） plays important role in trans-methyl reactions. Under the condition of drought （30% PEG）, salinity （200 mmol· L^-1 NaCl） and low temperature （4℃）, total RNA was extracted from the leaf and the first strand of cDNA was synthesized with reverse transcription. S-adenosylmethionine synthetase gene （SAMS gene） was amplified by PCR with the first strand cDNA as template and a pair of primers which was based on constructed ESTs sequence. Full-length SAMS gene sequence was obtained by BLAST comparison. According to the analysis, completed sequence of SAMS gene was integrality. The sequence of the SAMS gene was 1 185 bp in length with an opening reading frame （ORF） encoding 394 amino acids. The cDNA sequence showed a significant homology to the SAM genes from Phaseolus lunatus （89%）, Medicago sativa （85%）. A prokaryotic expression vectors based on pET-32b had been constructed and prokaryotic expression was analyzed in order to lay a strong foundation for resist adversity function analysis through situation of genic expression analysis.

Influences of Temperature Regime on Germination of Seed of Wild Soybean(Glycine soja)

As an important plant species with high protein contents,wild soybean(Glycine soja),has drawn much attention and appeared to be useful for the genetic improvement of soybean germplasms.Since temperature is one of the numerous environmental factors affecting the germination of most plants,an experimental study was carried out to determine the effect of temperature on germination of wild soybean(G.soja)seeds.Germination test was conducted by setting up thirty-six constant and alternating temperature regimes,ranging from 5 to 40 ℃(16 h night/8 h day).Responses in germination rate to these temperature regimes were then used to construct a quadratic response surface,giving estimated germination rates with confidence intervals at P ≤ 0.05.The results showed that germination capacity was significantly greater while exposed to constant temperatures of 25 ℃,and under the alternating temperature regime the optimum temperature occurred at the 20/25,25/25,25/30 ℃ regime(16 h/8 h)with the amplitude widened from 0 to 5 ℃.Together with regional monthly climate data,these results could be used to improve and promote the cultivation of wild soybean(G.soja),making it available to develop the location-specific optimum seeding time and to apply weed-control treatments.

Screening and evaluation for soybean resistance to Phakopsora pachyrhyzi in Glycine soja

Soybean rust caused by Phakopsora pachyrhizy is an important disease of soybean, and yield losses are very common in humid growing regions. Most commercial cultivars are susceptible and the disease is usually managed with fungicides. Resistance breeding is the most effective in controlling the disease. In this study, detached - leaf assay and greenhouse inoculation were used to screen 200 Glycine soja accessions for resistance to Phakopsora pachyrhizi in China. Most of the accessions were susceptible, and W8214 was the only accession that demonstrated RB resistance to Phakopsora pachyrhizy. The further repeated tests confirmed the resistance in W8214.

Inheritance of the Anatomy--Morphological Structure of the Stalk by Interspecific Hybrids of the Glycine L.

The research focuses on the study of anatomical and morphological stalk structure ofsoya interspecific hybrids of the third generation （F3） between （Glycine max （L.） Merr.） and G. soja Sieb. et Zucc. in comparison with parent plant species. The parent plant species and interspecific hybrids were sowed and grew under similar conditions. The similarity of the anatomic structure of stalks of cultivated plants and Glycine soja （wild soya） proves the hypothesis the studied species have the same origin. However, the obtained results show the considerable degree of phylogenetic dissociation between the studied soya species. Interspecific hybrids inherit from G. soja the ability to high intensive growth. The G. soja use in practical selective breeding is of great interest.

Sampling Strategy Within a Wild Soybean Population Based on Its Genetic Variation Detected by ISSR Markers

In order to determine an appropriate sampling strategy for the effective conservation of wild soybean (Glycine soja Sieb. et Zucc.) in China, a natural population from Jiangwan Airport in Shanghai was studied for its genetic diversity through the inter-simple sequence repeat (ISSR) marker analysis of a sample set consisting of 100 randomly collected individuals. A relatively large genetic diversity was detected among the samples based on estimation of DNA products amplified from 15 selected ISSR primers, with the similarity coefficient varying from 0.17 to 0.89. The mean expected heterozygosity (He) was 0.171 4 per locus, and Shannon index (1) was 0.271 4. The Principal Coordinate Analysis (PCA) further indicated that genetic diversity of the Jiangwan wild soybean population was not evenly distributed, instead, was presented by a mosaic or clustered distribution pattern. Correlation study between genetic diversity and number of samples demonstrated that genetic diversity increased dramatically with the increase of number of samples within 40 individuals, but the increase became slow and rapidly reached a plateau when more than 40 individuals were included in the analysis. It is concluded that (i) a sample set of approximately 35-45 individuals should be included to represent possibly high genetic diversity when conservation of a wild soybean population ex situ is undertaken; and (ii) collection of wild soybean samples should be spread out as wide as possible within a population, and a certain distance should be kept as intervals among individuals for sampling.

世界大豆生育阶段光温综合反应的地理分化和演化

【目的】大豆是短日喜温植物,对光温(日长、温度)条件敏感。大豆对光温反应的敏感性是大豆重要的驯化性状和适应性性状。在自然条件下,地理位置和/或播种季节是决定野生和栽培大豆分化的重要生态因素,这两个因素均是通过日长和温度等环境因素来调控大豆的生长发育。因而研究和比较野生和栽培大豆生长发育阶段光温综合反应特性的地理和季节分化,可以为大豆引种和适应性育种提供理论依据。【方法】选取1519份世界代表性野生和栽培大豆,在安徽当涂进行2年春播和夏播田间试验,使用播季间生育期差异作为品种光温综合反应敏感性(photo-thermal comprehensive response sensitivity,PTCRS)评价指标,研究各地理生态型大豆生长发育阶段的光温反应特性。【结果】(1)大豆的光温反应特性存在于生长发育的全过程。(2)野生大豆由南向北迁移时,生育前期和全生育期PTCRS减小,生育后期PTCRS增大,光温反应类型由前敏后钝变为前钝后敏,全生育期光温反应敏感。(3)野生大豆驯化为栽培大豆后,生育前期和全生育期PTCRS分别减小20%和16%,生育后期PTCRS变化较小,主要光温反应类型由前敏后钝变为前钝后敏和前钝后钝。(4)夏秋大豆和春大豆的全生育期PTCRS均表现由南向北逐渐减小;生育前期和生育后期PTCRS的地理分化则存在差异,其中,由南向北迁移时,夏秋大豆生育前期PTCRS减小、生育后期PTCRS先增后减,春大豆生育前期PTCRS无明显变化、生育后期PTCRS减小。(5)以中国黄淮和南方作为栽培大豆的起源中心,向北传播至中国东北、俄罗斯远东和瑞典南部,生育前期、后期和全生育期PTCRS均大幅减小;向东传播至朝鲜半岛和日本岛以及向西传播至北美北部、北美南部和中南美,生育前期和全生育期PTCRS减小,生育后期PTCRS无明显变化;向南传播至东南亚、南亚和非洲,生育前期和全生育期PTCRS增大、生育后期PTCRS无明显变化。(6)同一生态区不同生态型间PTCRS比较,春大豆生育前期、后期和全生育期PTCRS均最小,野生大豆生育前期PTCRS强于夏秋大豆,生育后期则表现相反,全生育期与夏秋大豆无显著差异。不同地理-播季生态型间PTCRS比较,生育前期PTCRS:南方野生大豆最敏感,其次是长江中下游野生大豆和南方夏秋大豆,然后是黄淮野生大豆和长江中下游夏秋大豆,余下地理生态型间无显著差异,均表现较钝感;生育后期PTCRS:长江中下游夏秋大豆最敏感,其次是东北和黄淮野生大豆及南方和黄淮夏秋大豆,余下地理生态型间差异较小,光温反应均较钝感;全生育期PTCRS:南方和长江中下游的野生及夏秋大豆间无显著差异,均表现敏感,其次是黄淮野生大豆,然后是东北野生大豆和黄淮夏秋大豆,春大豆PTCRS最小,且随纬度升高而显著减小。【结论】由地理和播季决定的光温综合条件是影响大豆生长发育的关键因素,不同地理-播季生态类型的野生和栽培大豆生育阶段对光温综合反应存在差异。中国黄淮及南方的栽培大豆向世界不同纬度的地理区域传播时,生育阶段光温综合反应的变化不同。全生育期光温反应敏感是大豆的原始性状,长江中下游的夏秋大豆可能为最具这种野生原始性状的栽培类型。

Changes in the Vascular Cylinder of Wild Soybean Roots Under Alkaline Stress

Changes in the vascular cylinder of wild soybean （Glycine soja Sieb. et Zucc） roots under alkaline stress were investigated in an experiment that applied 90 mmol L1 alkaline stress for 10 d at the five-trifoliate plant growth stage in Huinan County, Jilin Province, China. Root samples were collected and paraffin-cut sections were made, and the root structure was observed under an optical microscope. There were significant changes in the vascular cylinder of G. soja roots under alkaline stress. Root diameter was reduced and the vascular cylinder changed from tetrarch to triarch pattern. Alkaline stress resulted in reduced, diameters of root vessels, and a large amount of residual, alkaline solution was stained cyaneous in vessels. The paratracheal parenchymatous cells of the vessels were large and there was little secondary xylem. Thus, alkaline stress caused structural changes in the vascular cylinder of G. soja.

白洋淀野生大豆GsGST基因的克隆与鉴定

为进一步解析白洋淀野生大豆抵御盐胁迫的分子机制,本研究从白洋淀不同区域野生大豆种质资源中筛选获得高抗(salt tolerance,ST)与低抗(salt sensitive,SS)耐盐性不同的试验材料,并通过克隆获得野生大豆GsGST基因的开放阅读框序列(open reading frame,ORF),并对其编码蛋白进行了性质分析、结构预测及同源进化分析,同时对该基因表达模式进行了鉴定。研究结果表明,GsGST基因含有660 bp开放阅读框,编码219个氨基酸,α-螺旋和无规则卷曲是其整体蛋白质结构中的主要组成结构元件;野生大豆Gs GST蛋白具有亲水性,含有跨膜结构,位于细胞质中;同时该基因编码的蛋白与野生大豆Tau类谷胱甘肽S-转移酶(GsGSTU)的同源性较高,达到99.54%。在高盐(NaCl)非生物因子胁迫处理下,GsGST基因表现明显的上调表达趋势。本研究结果为白洋淀野生大豆的耐盐机制提供理论基础,为培育常规耐盐大豆新材料提供种质资源与关键基因。

Expanding the gene pool for soybean improvement with its wild relatives

Genetic diversity is a cornerstone of crop improvement,However,cultivated soybean(Glycine max)has undergone several genetic bottlenecks,including domestication in China,the introduction of landraces to other areas of the world and,latterly,selective breeding,leading to low genetic diversity the poses a major obstacle to soybean improvement.By contrast,there remains a relatively high level of genetic diversity in soybean's wild relatives,especially the perennial soybeans(Glycine subgenus Glycine),which could serve as potential gene pools for improving soybean cultivars.Wild soybeans are phylogenetically diversified and adapted to various habitats,harboring resistance to various biotic and abiotic stresses.Advances in genome and transcriptome sequencing enable alleles associated with desirable traits that were lost during domestication of soybean to be discovered in wild soybean.The collection and conservation of soybean wild relatives and the dissection of their genomic features will accelerate soybean breeding and facilitate sustainable agriculture and food production.

Current development and application of soybean genomics

Soybean (Glycine max), an important domesticated species originated in China, constitutes a major source ofedible oils and high-quality plant proteins worldwide. In spite of its complex genome as a consequence of an ancienttetraploidilization, platforms for map-based genomics, sequence-based genomics, comparative genomics and functionalgenomics have been well developed in the last decade, thus rich repertoires of genomic tools and resources are available,which have been influencing the soybean genetic improvement. Here we mainly review the progresses of soybean(including its wild relative Glycine soja) genomics and its impetus for soybean breeding, and raise the major biologicalquestions needing to be addressed. Genetic maps, physical maps, QTL and EST mapping have been so well achievedthat the marker assisted selection and positional cloning in soybean is feasible and even routine. Whole genomesequencing and transcriptomic analyses provide a large collection of molecular markers and predicted genes, which areinstrumental to comparative genomics and functional genomics. Comparative genomics has started to reveal theevolution of soybean genome and the molecular basis of soybean domestication process. Microarrays resources,mutagenesis and efficient transformation systems become essential components of soybean functional genomics.Furthermore, phenotypic functional genomics via both forward and reverse genetic approaches has inferred functionsof many genes involved in plant and seed development, in response to abiotic stresses, functioning in plant-pathogenicmicrobe interactions, and controlling the oil and protein content of seed. These achievements have paved the way forgeneration of transgenic or genetically modified (GM) soybean crops.