Chitooligosaccharide elicitor and oxylipins synergistically elevate phytoalexin production in rice
Chitooligosaccharide elicitor and oxylipins synergistically elevate phytoalexin production in rice
复制标题
DOI：
10.1007/s11103-021-01217-w
复制
发表时间：
2021-11-25
影响因子：
5.1
通讯作者：
Galis, Ivan
中科院分区：
文献类型：
--
作者：
Shinya, Tomonori;Miyamoto, Koji;Galis, Ivan
关键信息 我们发现，在水稻中，JA 前体 OPDA 的氨基酸缀合物可能作为与先天几丁质信号传导相协调的植物抗毒素生产的非典型信号。核心氧脂素、茉莉酸 (JA) 和 JA-Ile 是众所周知的植物防御坏死性病原体和/或食草动物的有效调节剂。然而，最近的研究还表明其他氧脂素，包括 12-氧代植物二烯酸 (OPDA)，可能有助于植物防御。在这里，我们使用先前表征的代谢防御标记物对香豆酰腐胺（CoP）和真菌激发子壳寡糖来专门测试水稻（Oryza sativa）中各种氧脂素的防御作用。虽然真菌激发子引发了 JA、JA-Ile 及其前体 OPDA 的快速产生，但用这些化合物进行外源处理的水稻细胞表明，OPDA（而不是 JA-Ile）可以刺激 CoP 的产生。接下来，使用反向遗传方法和氧脂素缺陷型水稻突变体（hebiba）将氧脂素与其他激发子触发的信号解偶联。看来，在没有氧脂素的情况下，残留的激发子信号传导仅具有最小的影响，但与 OPDA 协同作用，对 CoP 产生产生强烈的刺激活性。此外，由于 OPDA 处理的 Osjar1 突变细胞中的 CoP 水平受到损害，氧脂质-氨基酸缀合受损，因此假定的 OPDA-氨基酸缀合物成为 CoP 生物合成的假设调节剂。因此，我们在用外源 OPDA 处理的水稻细胞中发现了几种 OPDA-氨基酸缀合物，并且在用壳寡糖处理的水稻中检测到了 OPDA-Asp，尽管含量很少。然而，由于迄今为止合成的 OPDA-Asp 和 OPDA-Ile 未能在细胞中诱导 CoP，这表明另一种推测的 OPDA-氨基酸形式可能充当水稻中植物抗毒素的新型调节剂。
Key message We show that in rice, the amino acid-conjugates of JA precursor, OPDA, may function as a non-canonical signal for the production of phytoalexins in coordination with the innate chitin signaling. The core oxylipins, jasmonic acid (JA) and JA-Ile, are well-known as potent regulators of plant defense against necrotrophic pathogens and/or herbivores. However, recent studies also suggest that other oxylipins, including 12-oxo-phytodienoic acid (OPDA), may contribute to plant defense. Here, we used a previously characterized metabolic defense marker, p-coumaroylputrescine (CoP), and fungal elicitor, chitooligosaccharide, to specifically test defense role of various oxylipins in rice (Oryza sativa). While fungal elicitor triggered a rapid production of JA, JA-Ile, and their precursor OPDA, rice cells exogenously treated with the compounds revealed that OPDA, rather than JA-Ile, can stimulate the CoP production. Next, reverse genetic approach and oxylipin-deficient rice mutant (hebiba) were used to uncouple oxylipins from other elicitor-triggered signals. It appeared that, without oxylipins, residual elicitor signaling had only a minimal effect but, in synergy with OPDA, exerted a strong stimulatory activity towards CoP production. Furthermore, as CoP levels were compromised in the OPDA-treated Osjar1 mutant cells impaired in the oxylipin-amino acid conjugation, putative OPDA-amino acid conjugates emerged as hypothetical regulators of CoP biosynthesis. Accordingly, we found several OPDA-amino acid conjugates in rice cells treated with exogenous OPDA, and OPDA-Asp was detected, although in small amounts, in the chitooligosaccharide-treated rice. However, as synthetic OPDA-Asp and OPDA-Ile, so far, failed to induce CoP in cells, it suggests that yet another presumed OPDA-amino acid form(s) could be acting as novel regulator(s) of phytoalexins in rice.