由大豆疫黴菌引起的大豆疫黴根腐病是嚴重影響大豆生產的毀滅性病害之一，而病原菌中的Harpin蛋白具有提高作物病蟲害抗性的作用。最近，吉林大學潘紅玉和吉林農科院董英山團隊利用丁香假單胞菌中的hrpZm基因成功培育了具有大豆疫黴根腐病耐性的轉基因大豆。
革蘭氏陰性植物病原細菌hrp基因編碼的Harpin是一類廣譜性的蛋白激發子，能夠通過啟動植物防衛反應的方式，誘導植物抵禦病害。研究人員將菸草專化型的丁香假單胞菌——菸草野火病菌（P. syringae pv. tabaci）菌株Psta218中的Harpin蛋白編碼基因hrpZpsta進行了密碼子優化，得到hrpZm基因並轉化大豆品種Williams 82和Shennong 9。獲得的3個hrpZm基因超量表達的轉化事件表現出對大豆疫黴菌穩定、高效的耐受性。進一步分析顯示，大豆疫黴菌侵染後，水楊酸依賴型基因PR1、PR12、PAL和茉莉酸依賴型基因PPO以及超敏反應相關基因GmNPR1、RAR的表達量上調明顯。此外，轉基因大豆中與防禦反應相關的酶活性得到了極大程度的提升。這些結果表明，超表達hrpZm基因可以激發多個防禦信號途徑介導的抗病反應，從而提升大豆對疫黴根腐病的耐受性。
該研究為應對大豆疫黴根腐病提供了有效的解決方案。
Transgenic Research, 04 May 2018
Over-expression of the Pseudomonas syringae harpin-encoding gene hrpZm confers enhanced tolerance to Phytophthora root and stem rot in transgenic soybean
Author
Qian Du, Xiangdong Yang, Jinhua Zhang……Qiyun Li, Yingshan Dong, Hongyu Pan*
*: College of Plant Science, Jilin University, China
Abstract
Phytophthora root and stem rot (PRR) caused by Phytophthora sojae is one of the most devastating diseases reducing soybean (Glycine max) production all over the world. Harpin proteins in many plant pathogenic bacteria were confirmed to enhance disease and insect resistance in crop plants. Here, a harpin protein-encoding gene hrpZpsta from the P. syringaepv. tabaci strain Psta218 was codon-optimized (renamed hrpZm) and introduced into soybean cultivars Williams 82 and Shennong 9 by Agrobacterium-mediated transformation. Three independent transgenic lines over-expressing hrpZm were obtained and exhibited stable and enhanced tolerance to P. sojae infection in T2–T4 generations compared to the non-transformed (NT) and empty vector (EV)-transformed plants. Quantitative real-time PCR (qRT-PCR) analysis revealed that the expression of salicylic acid-dependent genes PR1, PR12, and PAL, jasmonic acid-dependent gene PPO, and hypersensitive response (HR)-related genes GmNPR1 and RAR was significantly up-regulated after P. sojae inoculation. Moreover, the activities of defense-related enzymes such as phenylalanine ammonia lyase (PAL), polyphenoloxidase (PPO), peroxidase, and superoxide dismutase also increased significantly in the transgenic lines compared to the NT and EV-transformed plants after inoculation. Our results suggest that over-expression of the hrpZm gene significantly enhances PRR tolerance in soybean by eliciting resistance responses mediated by multiple defense signaling pathways, thus providing an alternative approach for development of soybean varieties with improved tolerance against the soil-borne pathogen PRR.
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