Malnoy M, Jin Q, Borejsza-Wysocka E E, He S Y, Aldwinckle H S
Department of Plant Pathology, Cornell University, Geneva, NY 14456, USA.
Mol Plant Microbe Interact. 2007 Dec;20(12):1568-80. doi: 10.1094/MPMI-20-12-1568.
The NPR1 gene plays a pivotal role in systemic acquired resistance in plants. Its overexpression in Arabidopsis and rice results in increased disease resistance and elevated expression of pathogenesis-related (PR) genes. An NPR1 homolog, MpNPR1-1, was cloned from apple (Malus x domestica) and overexpressed in two important apple cultivars, Galaxy and M26. Apple leaf pieces were transformed with the MpNPR1 cDNA under the control of the inducible Pin2 or constitutive Cauliflower mosaic virus (CaMV)35S promoter using Agrobacterium tumefaciens. Overexpression of MpNPR1 mRNA was shown by reverse transcriptase-polymerase chain reaction. Activation of some PR genes (PR2, PR5, and PR8) was observed. Resistance to fire blight was evaluated in a growth chamber by inoculation of the shoot tips of our own rooted 30-cm-tall plants with virulent strain Ea273 of Erwinia amylovora. Transformed Galaxy lines overexpressing MpNPR1 had 32 to 40% of shoot length infected, compared with 80% in control Galaxy plants. Transformed M26 lines overexpressing MpNPR1 under the control of the CaMV35S promoter also showed a significant reduction of disease compared with control M26 plants. Some MpNPR-overexpressing Galaxy lines also exhibited increased resistance to two important fungal pathogens of apple, Venturia inaequalis and Gymnosporangium juniperi-virginianae. Selected transformed lines have been propagated for field trials for disease resistance and fruit quality.
NPR1基因在植物的系统获得性抗性中起关键作用。它在拟南芥和水稻中的过表达导致抗病性增强以及病程相关（PR）基因的表达升高。从苹果（Malus x domestica）中克隆了一个NPR1同源基因MpNPR1-1，并在两个重要的苹果品种Galaxy和M26中过表达。使用根癌农杆菌，将受诱导型Pin2或组成型花椰菜花叶病毒（CaMV）35S启动子控制的MpNPR1 cDNA转化苹果叶片切片。通过逆转录聚合酶链反应显示了MpNPR1 mRNA的过表达。观察到一些PR基因（PR2、PR5和PR8）的激活。在生长室中，通过用解淀粉欧文氏菌的强毒株Ea273接种我们自己培育的30厘米高植株的茎尖，评估对火疫病的抗性。过表达MpNPR1的转基因Galaxy品系有32%至40%的茎长受到感染，而对照Galaxy植株为80%。在CaMV35S启动子控制下过表达MpNPR1的转基因M26品系与对照M26植株相比，病害也显著减轻。一些过表达MpNPR的Galaxy品系对苹果的两种重要真菌病原体——苹果黑星病菌和苹果锈病菌也表现出增强的抗性。已选择转基因品系进行抗病性和果实品质的田间试验繁殖。
