In conclusion, plants defend themselves from insect or pathogen attack through a wide variety of mechanisms and stimulated by many different biotic inducers . Our results showed that SBPH feeding induced biochemical defense responses in the rice varieties Kasalath and Wuyujing 3. The activities of PAL, PPO and POD in Kasalath were almost identical to those in Wuyujing 3 when not infested by SBPH. These three enzymes were induced distinctly by SBPH challenge and their activities increased significantly. The combined action PD0332991 supplier of these defense enzymes may account for increased rice resistance to SBPH. PAL is the first enzyme of the phenylpropanoid pathway and is involved in the biosynthesis of phenolics, phytoalexins
and lignins . Our results indicated the increase
in PAL enzyme activity was consistent with the induction of PAL gene expression after SBPH feeding. The resulting phenolics could be oxidized by the action of PPO and POD to produce differently colored phenolic complexes or compounds such as quinines and even tannins . PPO usually accumulates upon wounding in plants . POD, meanwhile, is involved in lignin-forming plant defense responses and its activity is associated with disease resistance in plants, and increases in host plants following pathogen infection . Overall, our results revealed that the expression levels of the SA synthesis-related genes PAL, NPR1, EDS1 and PAD4 and PLX3397 mw the activities of defense-related enzymes such as PAL, POD, and PPO were highly induced in the resistant Kasalath rice in response to SBPH feeding, suggesting that the biosynthesis of salicylic acid, lignin, phenolic compounds and phytoalexins may contribute greatly to rice resistance mechanisms in the poorly studied rice–SBHP interaction system. This study was sponsored by the National
Nature Science Foundation of China (30971746) and the Major Project for Breeding Genetically Modified Organisms (2009ZX08009-046B). The authors are grateful to the comments of anonymous reviewers and editing from M. Blair. “
“Global mean air temperature has increased by about 0.74 °C during the past 100 years, and is predicted to increase by 2.0–5.4 °C by the end of 2100 . The elevation in the daily minimum temperature has been and will remain greater than that of the daily maximum temperature . An average annual increase in grain production of 44 million Orotic acid metric tons is required to meet worldwide food demands by 2050  and . Given that temperature is a key factor determining crop yield and quality, the anticipated warming may strongly affect future food security  and . Rice is one of the most important crops and a primary food source for more than half of the world’s population, and more than 90% of the world’s rice is produced and consumed in Asia . Thus, quantifying the impact of daily minimum temperature elevation on rice growth in Asia may assist in developing strategies for cropping adaptation to future climatic warming.