1 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; and.
2 University of Chinese Academy of Sciences, Beijing 100049, China.
Mol Plant Microbe Interact. 2019 Feb;32(2):255-266. doi: 10.1094/MPMI-06-18-0162-R. Epub 2018 Dec 12.
Stomata are leaf pores that regulate gas exchange and water transpiration in response to environmental cues. They also function in innate immunity by limiting pathogen entry through actively closing in so-called stomatal defense. However, roles of stomata in plant disease resistance are not fully elucidated, especially in monocots. Here, we report that non-race specific resistance of the rice abscisic acid-deficient mutant Osaba1 to Xanthomonas oryzae pv. oryzae is due to increased stomatal conductance. Reducing stomatal conductance in the Osaba1 mutant increases its susceptibility to X. oryzae pv. oryzae. Artificial opening of stomata in wild-type plants leads to enhanced resistance to X. oryzae pv. oryzae. The rice mutant es1-1 with constitutively higher stomatal conductance exhibits strong resistance to X. oryzae pv. oryzae. Additionally, Osaba1 and es1-1 are resistant to X. oryzae pv. oryzicola. The data support that open stomata confer postinvasive resistance against bacterial pathogens in rice, and such resistance probably results from decreased leaf water potential. Our findings reveal a novel role of stomata in plant immunity through modulation of leaf water status, which provides physiological insight into the interactions between plant, pathogen, and environment.
气孔是叶片上的孔，可根据环境信号调节气体交换和水分蒸腾。它们还通过主动关闭来限制病原体进入，从而在先天免疫中发挥作用，这种关闭被称为气孔防御。然而，气孔在植物抗病性中的作用尚未完全阐明，尤其是在单子叶植物中。在这里，我们报告说，水稻 ABA 缺陷突变体 Osaba1 对稻黄单胞菌 pv. 稻的非小种特异性抗性是由于气孔导度增加所致。降低 Osaba1 突变体的气孔导度会增加其对稻黄单胞菌 pv. 稻的敏感性。在野生型植物中人工打开气孔会导致对稻黄单胞菌 pv. 稻的抗性增强。具有持续较高气孔导度的水稻突变体 es1-1 对稻黄单胞菌 pv. 稻表现出强烈的抗性。此外，Osaba1 和 es1-1 还能抵抗稻黄单胞菌 pv. oryzicola。这些数据表明，张开的气孔赋予了水稻对细菌性病原体的入侵后抗性，这种抗性可能是由于叶片水势降低所致。我们的发现揭示了气孔通过调节叶片水分状况在植物免疫中的新作用，为植物、病原体和环境之间的相互作用提供了生理学上的深入了解。
