Instituto de Agricultura Sostenible, CSIC, Alameda del Obispo, Menéndez Pidal s/n, 14080 Córdoba, Spain.
Phytopathology. 2010 Jan;100(1):21-32. doi: 10.1094/PHYTO-100-1-0021.
Hypersensitive response (HR) against Blumeria graminis f. sp. hordei infection in barley (Hordeum vulgare) was associated with stomata "lock-up" leading to increased leaf water conductance (g(l)). Unique spatio-temporal patterns of HR formation occurred in barley with Mla1, Mla3, or MlLa R genes challenged with B. graminis f. sp. hordei. With Mla1, a rapid HR, limited to epidermal cells, arrested fungal growth before colonies initiated secondary attacks. With Mla3, mesophyll HR preceded that in epidermal cells whose initial survival supported secondary infections. With MlLa, mesophyll survived and not all attacked epidermal cells died immediately, allowing colony growth and secondary infection until arrested. Isolines with Mla1, Mla3, or MlLa genes inoculated with B. graminis f. sp. hordei ranging from 1 to 100 conidia mm(2) showed abnormally high g(l) during dark periods whose timing and extent correlated with those of each HR. Each isoline showed increased dark g(l) with the nonpathogen B. graminis f. sp. avenae which caused a single epidermal cell HR. Guard cell autofluorescence was seen only after drying of epidermal strips and closure of stomata suggesting that locked open stomata were viable. The data link stomatal lock-up to HR associated cell death and has implications for strategies for selecting disease resistant genotypes.
大麦（Hordeum vulgare）对禾本科布氏白粉菌（Blumeria graminis f. sp. hordei）感染的超敏反应（HR）与气孔“闭锁”有关，导致叶片水分传导率（g(l)）增加。具有 Mla1、Mla3 或 MlLa R 基因的大麦中，HR 的形成具有独特的时空模式，受到禾本科布氏白粉菌（B. graminis f. sp. hordei）的挑战。在 Mla1 中，快速 HR 局限于表皮细胞，在菌落发起二次攻击之前阻止真菌生长。在 Mla3 中，质体 HR 先于表皮细胞，其初始存活支持二次感染。在 MlLa 中，质体存活，并非所有受攻击的表皮细胞立即死亡，允许菌落生长和二次感染，直到被阻止。用 1 至 100 个分生孢子 mm(2)的禾本科布氏白粉菌（B. graminis f. sp. hordei）接种 Mla1、Mla3 或 MlLa 基因的等位基因系显示，在黑暗期出现异常高的 g(l)，其时间和程度与每个 HR 相关。每个等位基因系都显示出与非病原体禾本科布氏白粉菌（B. graminis f. sp. avenae）相关的黑暗 g(l)增加，后者引起单个表皮细胞 HR。仅在表皮条带干燥和气孔关闭后才观察到保卫细胞自发荧光，这表明闭锁的气孔是有活力的。该数据将气孔闭锁与 HR 相关的细胞死亡联系起来，这对选择抗病基因型的策略具有重要意义。
