Maize ZmFNSI Homologs Interact with an NLR Protein to Modulate Hypersensitive Response
Maize ZmFNSI Homologs Interact with an NLR Protein to Modulate Hypersensitive Response
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DOI：
10.3390/ijms21072529
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发表时间：
2020-04
影响因子：
5.6
通讯作者：
Yu-Xiu Zhu;Chunxia Ge;Shijun Ma;Xiao-ying Liu;Mengjie Liu;Yang Sun;Guan-Feng Wang
中科院分区：
文献类型：
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作者：
Yu-Xiu Zhu;Chunxia Ge;Shijun Ma;Xiao-ying Liu;Mengjie Liu;Yang Sun;Guan-Feng Wang
核苷酸结合、富含亮氨酸重复序列 (NLR) 蛋白是植物用来防御病原体感染的主要一类抗性 (R) 蛋白。 NLR 与其同源病原体效应子之间的识别通常会引发快速的局部细胞死亡，称为过敏反应 (HR)。黄酮合成酶 I (FNSI) 是黄酮生物合成途径中的关键酶之一。它还显示出水杨酸 (SA) 5-羟化酶 (S5H) 活性。 FNSI/S5H 的密切同源物具有 SA 3-羟化酶 (S3H) 活性。 FNSI/S5H和S3H在植物先天免疫中发挥重要作用。然而，在任何植物物种中，潜在的分子机制以及 S5H 和 S3H 与 NLR 介导的 HR 之间的关系尚不清楚。在这项研究中，我们鉴定了编码 ZmFNSI-1、ZmFNSI-2 和 ZmS3H 的三个基因，这些基因在携带自活性 NLR Rp1-D21 突变体的玉米品系中显着上调。功能分析表明，当在本塞姆氏烟草中瞬时表达时，ZmFNSI-1 和 ZmFNSI-2（而非 ZmS3H）抑制 Rp1-D21 及其信号结构域 CCD21 赋予的 HR。 ZmFNSI-1 和 ZmFNSI-2 与 CCD21 发生物理相互作用。此外，ZmFNSI-1和ZmFNSI-2与木质素生物合成途径中的关键酶HCT相互作用，也可以抑制Rp1-D21介导的HR。这些结果为进一步功能分析FNSI在植物先天免疫中的作用奠定了基础。
Nucleotide binding, leucine-rich-repeat (NLR) proteins are the major class of resistance (R) proteins used by plants to defend against pathogen infection. The recognition between NLRs and their cognate pathogen effectors usually triggers a rapid localized cell death, termed the hypersensitive response (HR). Flavone synthase I (FNSI) is one of the key enzymes in the flavone biosynthesis pathway. It also displays salicylic acid (SA) 5-hydroxylase (S5H) activity. A close homolog of FNSI/S5H displays SA 3-hydroxylase (S3H) activity. Both FNSI/S5H and S3H play important roles in plant innate immunity. However, the underlying molecular mechanisms and the relationship between S5H and S3H with the NLR-mediated HR are not known in any plant species. In this study, we identified three genes encoding ZmFNSI-1, ZmFNSI-2 and ZmS3H that are significantly upregulated in a maize line carrying an autoactive NLR Rp1-D21 mutant. Functional analysis showed that ZmFNSI-1 and ZmFNSI-2, but not ZmS3H, suppressed HR conferred by Rp1-D21 and its signaling domain CCD21 when transiently expressed in N. benthamiana. ZmFNSI-1 and ZmFNSI-2 physically interacted with CCD21. Furthermore, ZmFNSI-1 and ZmFNSI-2 interacted with HCT, a key enzyme in lignin biosynthesis pathway, which can also suppress Rp1-D21-mediated HR. These results lay the foundation for the further functional analysis of the roles of FNSI in plant innate immunity.