Leaf trichome formation is a very important agronomic trait as it confers resistance to biotic and abiotic stresses, but the causal genes involved in this process in B. juncea remain largely unexplored. In this study, we first characterized the haplotypes of BjB02.GL1 among different inbred lines with leaf trichomes or glabrous leaves. A comparative analysis of the number and density of leaf trichomes between the two mustard inbred lines was then performed. BSA analysis of leaves with trichomes and glabrous pools from the F2 segregating population mapped the candidate genes on Chr.A06 and Chr.B02. Two candidate genes, BjA06.GL1 and BjB02.GL1, were subsequently cloned. After sequence alignment of the BjGL1 genes, both SNPs and indel were identified in the BjA06.GL1 and BjB02.GL1 genes. And qRT–PCR analysis further confirmed that both the BjA06.GL1 and BjB02.GL1 genes were more highly expressed in leaves with trichomes than in glabrous leaves. As the leaf size increased, the leaf trichome density decreased. Gene editing of both BjA06.GL1 and BjB02.GL1 changed the leaf trichome to a glabrous leaf phenotype in mustard. In addition, plants with leaf trichomes presented greater resistance to aphids. Taken together, our results revealed that both BjA06.GL1 and BjB02.GL1 positively regulate leaf trichome formation and help increase aphid resistance in mustard. This study provides valuable resources and helps to elucidate the molecular mechanism of leaf trichome formation in B. juncea.

中文翻译：

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MYB 转录因子 BjA06.GL1 和 BjB02.GL1 的两个新等位基因控制芸苔属植物的叶毛并增强对蚜虫的抗性


叶毛状体的形成是一个非常重要的农艺性状，因为它赋予了对生物和非生物胁迫的抵抗力，但 B. juncea 中参与这一过程的致病基因在很大程度上仍未得到探索。在这项研究中，我们首先表征了 BjB02.GL1 在具有叶毛状体或无毛叶的不同自交系中的单倍型。然后对两种芥菜自交系之间叶毛的数量和密度进行了比较分析。对来自 F2 分离种群的具有毛状体和无毛池的叶子进行 BSA 分析，绘制了 Chr.A06 和 Chr.B02 上的候选基因。随后克隆了两个候选基因 BjA06.GL1 和 BjB02.GL1。BjGL1 基因序列比对后，在 BjA06.GL1 和 BjB02.GL1 基因中鉴定出 SNP 和 indel。qRT-PCR 分析进一步证实 BjA06.GL1 和 BjB02.GL1 基因在毛状体叶片中的表达高于无毛叶片。随着叶子大小的增加，叶毛密度降低。BjA06.GL1 和 BjB02.GL1 的基因编辑使芥菜的叶毛状体变为无毛叶表型。此外，具有叶毛状体的植物对蚜虫表现出更强的抵抗力。综上所述，我们的结果表明，BjA06.GL1 和 BjB02.GL1 均正向调节叶毛状体的形成，并有助于提高芥菜中的蚜虫抗性。本研究提供了宝贵的资源，有助于阐明 B. juncea 叶片毛状体形成的分子机制。