Maize resistance to insect herbivory is enhanced by silencing expression of genes for jasmonate-isoleucine degradation using sugarcane mosaic virus
Maize resistance to insect herbivory is enhanced by silencing expression of genes for jasmonate-isoleucine degradation using sugarcane mosaic virus
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DOI：
10.1002/pld3.407
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发表时间：
2022-06-01
期刊：
影响因子：
3
通讯作者：
Jander, Georg
中科院分区：
文献类型：
--
作者：
Chung, Seung Ho;Zhang, Shudi;Jander, Georg
以前，甘蔗花叶病毒(SCMV)是一种在玉米(Zea Mays)中瞬时表达外源基因的载体。在这里，我们表明，SCMV也可以用于病毒诱导的玉米内源基因的基因沉默(VIGS)。针对玉米植酸烯脱氢酶(PDS)的正义和反义VIGS构建的比较表明，反义构建导致基因表达的更大程度的降低。在针对PDS、病变模拟蛋白22(Les22)和Iodent Japan onica 1(Ij1)的VIGS构建体感染后的一段时间内，可以观察到SCMV感染后2、3和4周有效的表达沉默。然而，在第5周，Les22和Ij1的表达不再显著低于对照植株。防御信号分子茉莉酸-异亮氨酸(JA-Ile)可以被12C-羟基化和水解酶失活，这些基因的敲除导致对食草动物的抗性。JA-Ile羟基酶和水解酶已经在拟南芥、水稻和烟草中得到了研究。为了确定这些基因的玉米同源基因是否在植物防御中发挥作用，我们用SCMV通过VIGS沉默了ZmCYP94B1(预测的JA-Ile羟基酶)和ZmJIH1(预测的JA-Ile水解酶)的表达，从而导致两个与防御相关的基因玉米蛋白抑制物(MPI)和核糖体失活蛋白2(RIP2)的表达上调。虽然ZmCYP94131和ZmJIH1基因的表达沉默增加了对果夜蛾、美洲血吸虫和玉米叶蚜的抗性，但这两个基因的表达沉默没有相加效应。还需要进一步的工作来确定这些酶在调节玉米防御中的更精确的功能。
Previously, sugarcane mosaic virus (SCMV) was developed as a vector for transient expression of heterologous genes in Zea mays (maize). Here, we show that SCMV can also be applied for virus-induced gene silencing (VIGS) of endogenous maize genes. Comparison of sense and antisense VIGS constructs targeting maize phytoene desaturase (PDS) showed that antisense constructs resulted in a greater reduction in gene expression. In a time course of gene expression after infection with VIGS constructs targeting PDS, lesion mimic 22 (Les22), and Iodent japonica 1 (Ij1), efficient expression silencing was observed 2, 3, and 4 weeks after infection with SCMV. However, at Week 5, expression of Les22 and Ij1 was no longer significantly reduced compared with control plants. The defense signaling molecule jasmonate-isoleucine (JA-Ile) can be inactivated by 12C-hydroxylation and hydrolysis, and knockout of these genes leads to herbivore resistance. JA-Ile hydroxylases and hydrolases have been investigated in Arabidopsis, rice, and Nicotiana attenuata. To determine whether the maize homologs of these genes function in plant defense, we silenced expression of ZmCYP94B1 (predicted JA-Ile hydroxylase) and ZmJIH1 (predicted JA-Ile hydrolase) by VIGS with SCMV, which resulted in elevated expression of two defense-related genes, Maize Proteinase Inhibitor (MPI) and Ribosome Inactivating Protein 2 (RIP2). Although ZmCYP94131 and ZmJIH1 gene expression silencing increased resistance to Spodoptera frugiperda (fall armyworm), Schistocerca americana (American birdwing grasshopper), and Rhopalosiphum maidis (corn leaf aphid), there was no additive effect from silencing the expression of both genes. Further work will be required to determine the more precise functions of these enzymes in regulating maize defenses.