RNAi of the sesquiterpene cyclase gene for phytoalexin production impairs pre‐ and post‐invasive resistance to potato blight pathogens
RNAi of the sesquiterpene cyclase gene for phytoalexin production impairs pre‐ and post‐invasive resistance to potato blight pathogens
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DOI：
10.1111/mpp.12802
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发表时间：
2019-04
影响因子：
4.9
通讯作者：
Miki Yoshioka;Ayako Adachi;Yutaka Sato;N. Doke;T. Kondo;H. Yoshioka
中科院分区：
文献类型：
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作者：
Miki Yoshioka;Ayako Adachi;Yutaka Sato;N. Doke;T. Kondo;H. Yoshioka
马铃薯抗微生物倍半萜类植物抗毒素lubimin和rishitin涉及对晚疫病病原体致病疫霉和早疫病病原体早疫病链格孢的抗性。为了研究植物抗毒素在马铃薯防御中的作用，我们构建了转基因马铃薯植株，其中倍半萜环化酶是产生鲁比明和rishitin的关键酶。转基因块茎缺乏植物抗毒素，对致病疫霉的无毒分离株表现出降低的侵入后抗性，导致成功感染第一个被攻击的细胞而不诱导细胞死亡。然而，在随后穿透的细胞中观察到细胞死亡。虽然我们未能在野生型叶片的提取物中检测到植物抗毒素和抗真菌活性，但转基因叶片对无毒致病疫霉的入侵后抗性降低。另一方面，A. Solani经常穿透转基因叶片的表皮细胞，并引起严重的疾病症状，推测是由于缺乏未鉴定的抗真菌化合物。抗微生物组分对穿透抗性和随后定殖的贡献可能取决于病原体物种而变化，表明倍半萜环化酶介导的化合物参与对坏死营养型病原体A的侵入前抗性。solani和对半活体营养型病原体致病疫霉的侵入后抗性。
Summary Potato antimicrobial sesquiterpenoid phytoalexins lubimin and rishitin have been implicated in resistance to the late blight pathogen, Phytophthora infestans and early blight pathogen, Alternaria solani. We generated transgenic potato plants in which sesquiterpene cyclase, a key enzyme for production of lubimin and rishitin, is compromised by RNAi to investigate the role of phytoalexins in potato defence. The transgenic tubers were deficient in phytoalexins and exhibited reduced post‐invasive resistance to an avirulent isolate of P. infestans, resulting in successful infection of the first attacked cells without induction of cell death. However, cell death was observed in the subsequently penetrated cells. Although we failed to detect phytoalexins and antifungal activity in the extract from wild‐type leaves, post‐invasive resistance to avirulent P. infestans was reduced in transgenic leaves. On the other hand, A. solani frequently penetrated epidermal cells of transgenic leaves and caused severe disease symptoms presumably from a deficiency in unidentified antifungal compounds. The contribution of antimicrobial components to resistance to penetration and later colonization may vary depending on the pathogen species, suggesting that sesquiterpene cyclase‐mediated compounds participate in pre‐invasive resistance to necrotrophic pathogen A. solani and post‐invasive resistance to hemibiotrophic pathogen P. infestans.