Pathak N, Bhaduri A, Bhat K V, Rai A K
Centre for Advanced Study in Botany, Banaras Hindu University, Varanasi, India.
Division of Genomic Resources, National Bureau of Plant Genetic Resources, New Delhi, India.
Plant Biol (Stuttg). 2015 Sep;17(5):1039-46. doi: 10.1111/plb.12327. Epub 2015 Apr 9.
Sesamin and sesamolin are the major oil-soluble lignans present in sesame seed, having a wide range of biological functions beneficial to human health. Understanding sesame domestication history using sesamin synthase gene expression could enable delineation of the sesame putative progenitor. This report examined the functional expression of sesamin synthase (CYP81Q1) during capsule maturation (0-40 days after flowering) in three wild Sesamum species and four sesame cultivars. Among the cultivated accessions, only S. indicum (CO-1) exhibited transcript abundance of sesamin synthase along with high sesamin content similar to S. malabaricum, while the other cultivated sesame showed low expression. The sesamin synthase expression analysis, coupled with quantification of sesamin level, indicates that sesamin synthase was not positively favoured during domestication. The sesamin synthase expression pattern and lignan content, along with phylogenetic analysis suggested a close relationship of cultivated sesame and the wild species S. malabaricum. The high genetic identity between the two species S. indicum and S. malabaricum points towards the role of the putative progenitor S. malabaricum in sesame breeding programmes to broaden the genetic base of sesame cultivars. This study emphasises the need to investigate intraspecific and interspecific variation in the primary, secondary and tertiary gene pools to develop superior sesame genotypes.
芝麻素和芝麻林素是芝麻籽中主要的油溶性木脂素，具有多种对人体健康有益的生物学功能。利用芝麻素合成酶基因表达来了解芝麻的驯化历史，有助于勾勒出芝麻假定的祖先。本报告研究了三种野生芝麻属物种和四个芝麻品种在蒴果成熟（开花后0 - 40天）期间芝麻素合成酶（CYP81Q1）的功能表达。在栽培品种中，只有印度芝麻（CO - 1）表现出与马拉巴芝麻相似的芝麻素合成酶转录丰度以及高芝麻素含量，而其他栽培芝麻的表达较低。芝麻素合成酶表达分析以及芝麻素水平的定量表明，芝麻素合成酶在驯化过程中并未受到正向选择。芝麻素合成酶的表达模式、木脂素含量以及系统发育分析表明，栽培芝麻与野生种马拉巴芝麻关系密切。印度芝麻和马拉巴芝麻这两个物种之间的高遗传同一性表明，假定的祖先马拉巴芝麻在芝麻育种计划中对于拓宽芝麻品种的遗传基础具有重要作用。本研究强调有必要研究初级、次级和三级基因库中的种内和种间变异，以培育出优良的芝麻基因型。
