Scalschi Loredana, Sanmartín Maite, Camañes Gemma, Troncho Pilar, Sánchez-Serrano José J, García-Agustín Pilar, Vicedo Begonya
Grupo de Bioquímica y Biotecnología, Área de Fisiología Vegetal, Departament de Ciències Agràries i del Medi Natural, ESTCE, Universitat Jaume I, Castellón, 12071, Spain.
Plant J. 2015 Jan;81(2):304-15. doi: 10.1111/tpj.12728. Epub 2014 Dec 22.
Cis-(+)-12-oxo-phytodienoic acid (OPDA) is likely to play signaling roles in plant defense that do not depend on its further conversion to the phytohormone jasmonic acid. To elucidate the role of OPDA in Solanum lycopersicum (tomato) plant defense, we have silenced the 12-oxophytodienoate reductase 3 (OPR3) gene. Two independent transgenic tomato lines (SiOPR3-1 and SiOPR3-2) showed significantly reduced OPR3 expression upon infection with the necrotrophic pathogen Botrytis cinerea. Moreover, SiOPR3 plants are more susceptible to this pathogen, and this susceptibility is accompanied by a significant decrease in OPDA levels and by the production of JA-Ile being almost abolished. OPR3 silencing also leads to a major reduction in the expression of other genes of the jasmonic acid (JA) synthesis and signaling pathways after infection. These results confirm that in tomato plants, as in Arabidopsis, OPR3 determines OPDA availability for JA biosynthesis. In addition, we show that an intact JA biosynthetic pathway is required for proper callose deposition, as its pathogen-induced accumulation is reduced in SiOPR3 plants. Interestingly, OPDA, but not JA, treatment restored basal resistance to B. cinerea and induced callose deposition in SiOPR3-1 and SiOPR3-2 transgenic plants. These results provide clear evidence that OPDA by itself plays a major role in the basal defense of tomato plants against this necrotrophic pathogen.
顺式-(+)-12-氧代植物二烯酸（OPDA）可能在植物防御中发挥不依赖于其进一步转化为植物激素茉莉酸的信号传导作用。为了阐明OPDA在番茄植物防御中的作用，我们使12-氧代植物二烯酸还原酶3（OPR3）基因沉默。两个独立的转基因番茄品系（SiOPR3-1和SiOPR3-2）在感染坏死营养型病原菌灰葡萄孢后，OPR3表达显著降低。此外，SiOPR3植物对这种病原菌更敏感，这种敏感性伴随着OPDA水平的显著降低以及茉莉酸异亮氨酸（JA-Ile）的产生几乎被消除。OPR3沉默还导致感染后茉莉酸（JA）合成和信号通路的其他基因表达大幅降低。这些结果证实，在番茄植物中，如同在拟南芥中一样，OPR3决定了用于JA生物合成的OPDA的可用性。此外，我们表明完整的JA生物合成途径对于正确的胼胝质沉积是必需的，因为在SiOPR3植物中病原菌诱导的胼胝质积累减少。有趣的是，用OPDA而非JA处理可恢复对灰葡萄孢的基础抗性，并在SiOPR3-1和SiOPR3-2转基因植物中诱导胼胝质沉积。这些结果提供了明确的证据，表明OPDA自身在番茄植物对这种坏死营养型病原菌的基础防御中起主要作用。
