Jia Guogeng, Thinn Khaing Shwe Zin, Kim Sun Ha, Min Jiyoung, Oh Sang-Keun
Department of Applied Biology, Chungnam National University, Daejeon 34134, Korea.
Plant Pathol J. 2024 Oct;40(5):512-524. doi: 10.5423/PPJ.OA.07.2024.0104. Epub 2024 Oct 1.
Transcription factors (TFs) regulate gene expression by binding to DNA. The NAC gene family in plants consists of crucial TFs that influence plant development and stress responses. The whole genome of Capsicum annuum shows over 100 NAC genes (CaNAC). Functional characteristics of the most CaNAC TFs are unknown. In this study, we identified CaNAC4, a novel NAC TF in C. annuum. CaNAC4 expression increased after inoculation with the pathogens, Xanthomonas axonopodis pv. vesicatoria race 3 and X. axonopodis pv. glycines 8ra, and following treatment with the plant hormones, salicylic acid and abscisic acid. We investigated the functional characteristics of the CaNAC4 gene and its roles in salt tolerance and anti-pathogen defense in transgenic Nicotiana benthamiana. For salt stress analysis, the leaf discs of wild-type and CaNAC4-transgenic N. benthamiana plants were exposed to different concentrations of sodium chloride. Chlorophyll loss was more severe in salt stress-treated wild-type plants than in CaNAC4-transgenic plants. To analyze the role of CaNAC4 in anti-pathogen defense, a spore suspension of Botrytis cinerea was used to infect the leaves. The disease caused by B. cinerea gradually increased in severity, and the symptoms were clearer in the CaNAC4-transgenic lines. We also investigated hypersensitive response (HR) in CaNAC4-transgenic plants. The results showed a stronger HR in wild-type plants after infiltration with the apoptosis regulator, BAX. In conclusion, our results suggest that CaNAC4 may enhance salt tolerance and act as a negative regulator of biotic stress in plants.
转录因子（TFs）通过与DNA结合来调控基因表达。植物中的NAC基因家族由影响植物发育和应激反应的关键转录因子组成。辣椒的全基因组显示有超过100个NAC基因（CaNAC）。大多数CaNAC转录因子的功能特性尚不清楚。在本研究中，我们鉴定了辣椒中的一种新型NAC转录因子CaNAC4。接种病原菌野油菜黄单胞菌辣椒斑点病致病变种3和大豆灰斑病菌8ra后，以及用植物激素水杨酸和脱落酸处理后，CaNAC4的表达增加。我们研究了CaNAC4基因的功能特性及其在转基因本氏烟草耐盐性和抗病原体防御中的作用。对于盐胁迫分析，将野生型和CaNAC4转基因本氏烟草植株的叶片圆盘暴露于不同浓度的氯化钠中。盐胁迫处理的野生型植株的叶绿素损失比CaNAC4转基因植株更严重。为了分析CaNAC4在抗病原体防御中的作用，使用灰葡萄孢的孢子悬浮液感染叶片。由灰葡萄孢引起的病害严重程度逐渐增加，且在CaNAC4转基因株系中症状更明显。我们还研究了CaNAC4转基因植株中的过敏反应（HR）。结果显示，在用凋亡调节因子BAX浸润后，野生型植株中的HR更强。总之，我们的结果表明CaNAC4可能增强植物的耐盐性，并作为植物生物胁迫的负调节因子。
