Jun Wang1,2,3, Jia Song1,2,3, Xiao-Bao Wu1,2,3, Qian-Qian Deng1,2,3, Zhong-Yan Zhu1,2,3, Ming-Jian Ren4, Mao Ye1,2,3, Ren-Sen Zeng5. 1. Institute of Entomology, Guizhou University, Guiyang, China. 2. Guizhou Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Guiyang, China. 3. Scientific Observing and Experimental Station of Crop Pests in Guiyang, Ministry of Agriculture, Guiyang, China. 4. Guizhou Branch of the National Wheat Improvement Center, Guiyang, China. 5. Key Laboratory of the Ministry of Education for Genetics, Breeding, and Multiple Uses of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China.
Abstract
BACKGROUND: Calcium is an essential macronutrient for plant growth. Although it has been shown that exogenous Ca application can increase plant resistance to abiotic stress, little is known about its potential to enhance plant tolerance to biotic stress. Here, we investigated whether pretreatment of wheat (Triticum aestivum L.) seeds with calcium chloride (CaCl2 ) improves plant resistance against wheat aphid (Schizaphis graminum Rondani). The developmental time, population size, feeding behavior of aphids on plants grown from CaCl2 - and water-pretreated seeds, and plant defense responses to aphid attack were investigated. RESULTS: Seed pretreatment with CaCl2 extended aphid development time and reduced aphid population size and feeding efficiency. In addition, the pretreatment significantly increased the concentration of Ca2+ in wheat leaves, and upregulated expression levels of TaCaM genes and callose synthase genes (TaGSL2, TaGSL8, TaGSL10, TaGSL12, TaGSL19, TaGSL22 and TaGSL23). Callose concentration in the leaves of plants grown from CaCl2 -pretreated seeds increased significantly upon aphid attack. Further, callose deposition was observed mainly in the phloem. CONCLUSION: These results suggest that seed pretreatment with CaCl2 primes the plant response against wheat aphid attack, leading to modulation of callose deposition in the phloem in response to aphid attack.
BACKGROUND:Calcium is an essential macronutrient for plant growth. Although it has been shown that exogenous Ca application can increase plant resistance to abiotic stress, little is known about its potential to enhance plant tolerance to biotic stress. Here, we investigated whether pretreatment of wheat (Triticum aestivum L.) seeds with calcium chloride (CaCl2 ) improves plant resistance against wheat aphid (Schizaphis graminum Rondani). The developmental time, population size, feeding behavior of aphids on plants grown from CaCl2 - and water-pretreated seeds, and plant defense responses to aphid attack were investigated. RESULTS: Seed pretreatment with CaCl2 extended aphid development time and reduced aphid population size and feeding efficiency. In addition, the pretreatment significantly increased the concentration of Ca2+ in wheat leaves, and upregulated expression levels of TaCaM genes and callose synthase genes (TaGSL2, TaGSL8, TaGSL10, TaGSL12, TaGSL19, TaGSL22 and TaGSL23). Callose concentration in the leaves of plants grown from CaCl2 -pretreated seeds increased significantly upon aphid attack. Further, callose deposition was observed mainly in the phloem. CONCLUSION: These results suggest that seed pretreatment with CaCl2 primes the plant response against wheat aphid attack, leading to modulation of callose deposition in the phloem in response to aphid attack.