Draft genome sequence of a less-known wild Vigna: Beach pea(V. marina cv. ANBp-14-03)

Beach pea or beach cowpea(Vigna marina(Burm.)Merr.)belongs to the family Fabaceae.It is a close relative of cultivated Vigna species such as adzuki bean(V.angularis),cowpea(V.unguiculata),mung bean(V.radiata),and blackgram(V.mungo),and is distributed throughout the tropics.With its ability to tolerate salt stress,beach pea has great potential to contribute salt-tolerance genes for developing salt-tolerant cultivars in cultivated Vigna species.However,it is still underutilized in Vigna breeding programs.A draft genome sequence of beach pea was generated using a high-throughput next-generation sequencing platform,yielding 23.7 Gb of sequence from 79,929,868 filtered reads.A de novo genome assembly containing 68,731 scaffolds gave an N50 length of 10,272 bp and the assembled sequences totaled 365.6 Mb.A total of 35,448 SSRs,including 3574 compound SSRs,were identified and primer pairs for most of these SSRs were designed.Genome analysis identified 50,670 genes with mean coding sequence length 1042 bp.Phylogenetic analysis revealed highest sequence similarity with V.angularis,followed by V.radiata.Comparison with the V.angularis genome revealed 16,699 SNPs and 2253 InDels and comparison with the V.radiata genome revealed 17,538 SNPs and 2300 InDels.To our knowledge this is the first draft genome sequence of beach pea derived from an accession(ANBp-14-03)adapted locally in the Andaman and Nicobar Islands of India.The draft genome sequence may facilitate the genetic enhancement in cultivated Vigna species.

6种豇豆属植物耐盐性评价及光合特性研究

采用沙培方法,研究盐胁迫(300 mmol/L)对6种豇豆属植物幼苗生长及光合特性的影响。结果表明:(1)盐处理6 d后,贼小豆的叶绿素(Chlorophyll,Chl)含量显著降低,叶片相对含水量(Relative Water Content,RWC)、质膜透性(Electrolyte Leakage,EL)和枯叶率(Withered Leaf Rate,WLR)显著增加,而滨豇豆均没有显著差异;主成分分析、相关分析及隶属函数分析结果表明,WLR与EL呈极显著正相关,RWC、Chl含量呈显著负相关;主成分分析得到2个主成分PC1和PC2,可以解释总变化的92.75%;隶属函数排名表明,滨豇豆的耐盐能力最好,贼小豆最差。(2)滨豇豆的净光合速率(Pn)、胞间CO2浓度(Ci)、气孔导度(Gs)、蒸腾速率(Tr)、PSⅡ最大光化学效率(Fv/Fm)和最大荧光产量(Fm)、PSⅡ非调节性能量耗散[Y(NO)]均没有显著差异,而贼小豆除Y(NO)显著增加外,其余均显著降低。

NaCl对2种豇豆属植物种子萌发和幼苗生长的影响

盐碱地在中国广泛分布,筛选耐盐型牧草对充分利用及改良盐碱地具有重要意义。以2种豇豆属植物滨豇豆和赤小豆为材料,采用0%,0.5%,1.0%,1.5%四种浓度的Na Cl模拟盐胁迫,研究盐胁迫对这2种豇豆属植物种子萌发及幼苗生长的影响。结果表明:随着盐浓度的升高,滨豇豆和赤小豆的种子萌发和幼苗生长受到明显抑制,主要体现在,发芽率、发芽势、发芽指数、根长、胚轴长和幼苗相对含水量都随盐浓度的升高呈下降趋势;和赤小豆相比,滨豇豆的活力指数在不同浓度盐处理下差异不显著,且高盐浓度下其胚轴显著长于赤小豆,表现出较好的耐盐性。