Sra Simarjeet Kaur, Sharma Meha, Kaur Gurpreet, Sharma Sanjula, Akhatar Javed, Sharma Anju, Banga S S
School of Agricultural Biotechnology, Punjab Agricultural University, Ludhiana, 141004, India.
Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana, 141004, India.
Mol Biol Rep. 2019 Feb;46(1):1227-1238. doi: 10.1007/s11033-019-04591-3. Epub 2019 Jan 12.
Seed size and seed metabolites have been the targets of direct or indirect selection during domestication and subsequent crop breeding. Understanding these traits and associated genetics can prove very useful for plant translational research. Large germplasm assemblage (235) of Brassica juncea and its progenitor species (B. rapa and B. nigra) was evaluated to establish seed trait variations for seed size and seed metabolites. Seeds were smallest in B. nigra and largest in B. juncea. Australian B. juncea and Indian B. rapa var brown sarson types averaged more seed oil content. Seed size and oil content were generally higher in modern cultivars in comparison to the land races. Allelic diversity for known associated genes for seed-size and oil-content (AP2, ARF2, TTG2, GRF2, GL2, CYP78A5, CYP78A6, MINI3, IKU2, IKU1, BRI1, DGAT, GPDH, LPAAT, GPAT and DA1) was studied so as to infer the effect of domestication on seed traits. Three genes (IKU1, IKU2, AP2) in B. rapa, two (TTG2 and GL2) in B. nigra and two (IKU1 and GRF2) in natural B. juncea were identified as targets of selection on the basis of Fst outlier and/or sequence diversity tests. We report parallel divergence for seed traits between B. juncea and B. rapa. Directional selection appeared stronger for seed-size as compared to correlated seed metabolites. Positive selection on seed-size is likely to have played a significant role in structuring regional variation in the germplasm.
在驯化及后续作物育种过程中，种子大小和种子代谢产物一直是直接或间接选择的目标。了解这些性状及其相关遗传学知识对植物转化研究非常有用。对芥菜及其亲本物种（白菜和黑芥）的大量种质集合（235份）进行了评估，以确定种子大小和种子代谢产物的种子性状变异。黑芥的种子最小，芥菜的种子最大。澳大利亚芥菜和印度白菜变种棕色萨尔逊类型的种子平均含油量更高。与地方品种相比，现代品种的种子大小和含油量通常更高。研究了种子大小和含油量已知相关基因（AP2、ARF2、TTG2、GRF2、GL2、CYP78A5、CYP78A6、MINI3、IKU2、IKU1、BRI1、DGAT、GPDH、LPAAT、GPAT和DA1）的等位基因多样性，以推断驯化对种子性状的影响。根据Fst离群值和/或序列多样性测试，确定白菜中的三个基因（IKU1、IKU2、AP2）、黑芥中的两个基因（TTG2和GL2）以及天然芥菜中的两个基因（IKU1和GRF2）为选择目标。我们报告了芥菜和白菜在种子性状上的平行分化。与相关的种子代谢产物相比，种子大小的定向选择似乎更强。种子大小的正选择可能在构建种质区域变异中发挥了重要作用。
