Gómez-Ariza Jorge, Campo Sonia, Rufat Mar, Estopà Montserrat, Messeguer Joaquima, San Segundo Blanca, Coca María
Departamento de Genética Molecular, Laboratorio de Genética Molecular Vegetal, Consorcio CSIC-IRTA, Jordi Girona 18, 08034 Barcelona, Spain.
Mol Plant Microbe Interact. 2007 Jul;20(7):832-42. doi: 10.1094/MPMI-20-7-0832.
Expression of pathogenesis-related (PR) genes is part of the plant's natural defense response against pathogen attack. The PRms gene encodes a fungal-inducible PR protein from maize. Here, we demonstrate that expression of PRms in transgenic rice confers broad-spectrum protection against pathogens, including fungal (Magnaporthe oryzae, Fusarium verticillioides, and Helminthosporium oryzae) and bacterial (Erwinia chrysanthemi) pathogens. The PRms-mediated disease resistance in rice plants is associated with an enhanced capacity to express and activate the natural plant defense mechanisms. Thus, PRms rice plants display a basal level of expression of endogenous defense genes in the absence of the pathogen. PRms plants also exhibit stronger and quicker defense responses during pathogen infection. We also have found that sucrose accumulates at higher levels in leaves of PRms plants. Sucrose responsiveness of rice defense genes correlates with the pathogen-responsive priming of their expression in PRms rice plants. Moreover, pretreatment of rice plants with sucrose enhances resistance to M. oryzae infection. Together, these results support a sucrose-mediated priming of defense responses in PRms rice plants which results in broad-spectrum disease resistance.
病程相关（PR）基因的表达是植物对病原体攻击的天然防御反应的一部分。PRms基因编码一种来自玉米的真菌诱导型PR蛋白。在此，我们证明PRms在转基因水稻中的表达赋予了对病原体的广谱保护，包括真菌病原体（稻瘟病菌、串珠镰孢菌和稻长蠕孢菌）和细菌病原体（菊欧文氏菌）。水稻植株中PRms介导的抗病性与表达和激活天然植物防御机制的能力增强有关。因此，PRms水稻植株在没有病原体的情况下表现出内源性防御基因的基础表达水平。PRms植株在病原体感染期间也表现出更强、更快的防御反应。我们还发现蔗糖在PRms植株的叶片中积累水平更高。水稻防御基因的蔗糖反应性与其在PRms水稻植株中病原体响应引发的表达相关。此外，用蔗糖预处理水稻植株可增强对稻瘟病菌感染的抗性。总之，这些结果支持了蔗糖介导的PRms水稻植株防御反应引发，从而导致广谱抗病性。
