ABSTRACT

Coleoptile/mesocotyl elongation influence seedling emergence and establishment, is major causes of maize deep-seeding tolerance (DST). Detailed analyses on molecular basis underlying their elongation mediated by brassinosteroid under deep-seeding stress (DSS) could provide meaningful information for key factors controlling their elongation. Here we monitored transcriptome and phytohormones changes specifically in elongating coleoptile/mesocotyl in response to DSS and 24-epibrassinolide (EBR)-signaling. Phenotypically, contrasting maize evolved variant organs to positively respond to DST, longer coleoptile/mesocoty of K12/W64A was a desirable organ for seedling under DSS. Applied-EBR improved maize DST, and their coleoptiles/mesocotyls were further elongated. 15,607/20,491 differentially expressed genes (DEGs) were identified in W64A/K12 coleoptile, KEGG analysis showed plant hormone signal transduction, starch and sucrose metabolism, valine, leucine, and isoleucine degradation were critical processes of coleoptile elongation under DSS and EBR signaling, further highly interconnected network maps including 79/142 DEGs for phytohormones were generated. Consistent with these DEGs expression, interactions, and transport, IAA, GA₃, ABA, and Cis-ZT were significantly reduced while EBR, Trans-ZT, JA, and SA were clearly increased in coleoptile under DSS and EBR-signaling. These results enrich our knowledge about the genes and phytohormones regulating coleoptile elongation in maize, and help improve future studies on corresponding genes and develop varieties with DST.

摘要

胚芽鞘/中胚轴伸长影响幼苗的出苗和定植，是玉米耐深播（DST）的主要原因。详细分析油菜素内酯在深播应力（DSS）下其伸长的分子基础可以为控制其伸长的关键因素提供有意义的信息。在这里，我们监测了响应于 DSS 和 24-表油菜素 (EBR) 信号传导的延长胚芽鞘/中胚轴的转录组和植物激素变化。在表型上，对比玉米进化出的变异器官对 DST 有积极反应，较长的 K12/W64A 胚芽鞘/中胚轴是 DSS 下幼苗的理想器官。Applied-EBR改善了玉米DST，其胚芽鞘/中胚轴进一步伸长。在 W64A/K12 胚芽鞘中鉴定出 15,607/20,491 个差异表达基因 (DEG)，KEGG分析表明，植物激素信号转导、淀粉和蔗糖代谢、缬氨酸、亮氨酸和异亮氨酸降解是DSS和EBR信号下胚芽鞘伸长的关键过程，生成了包括79/142°植物激素在内的高度互联网络图。与这些 DEG 表达、相互作用和运输一致，IAA，GA_如图3所示，在DSS和EBR信号下，胚芽鞘中ABA和Cis-ZT显着降低，而EBR、Trans-ZT、JA和SA明显增加。这些结果丰富了我们对调控玉米胚芽鞘伸长的基因和植物激素的认识，并有助于改进对相应基因的未来研究和开发具有DST的品种。