RNA-Seq Analysis Reveals MAPKKK Family Members Related to Drought Tolerance in Maize |
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Authors: | Ya Liu Miaoyi Zhou Zhaoxu Gao Wen Ren Fengling Yang Hang He Jiuran Zhao |
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Affiliation: | 1. Maize Research Center, Beijing Academy of Agricultural and Forestry Science, Beijing 100097, P.R.China.; 2. School of Life Sciences and School of Advanced Agriculture Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, P.R.China.; Estación Experimental del Zaidín (CSIC), SPAIN, |
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Abstract: | The mitogen-activated protein kinase (MAPK) cascade is an evolutionarily conserved signal transduction pathway that is involved in plant development and stress responses. As the first component of this phosphorelay cascade, mitogen-activated protein kinase kinase kinases (MAPKKKs) act as adaptors linking upstream signaling steps to the core MAPK cascade to promote the appropriate cellular responses; however, the functions of MAPKKKs in maize are unclear. Here, we identified 71 MAPKKK genes, of which 14 were novel, based on a computational analysis of the maize (Zea mays L.) genome. Using an RNA-seq analysis in the leaf, stem and root of maize under well-watered and drought-stress conditions, we identified 5,866 differentially expressed genes (DEGs), including 8 MAPKKK genes responsive to drought stress. Many of the DEGs were enriched in processes such as drought stress, abiotic stimulus, oxidation-reduction, and metabolic processes. The other way round, DEGs involved in processes such as oxidation, photosynthesis, and starch, proline, ethylene, and salicylic acid metabolism were clearly co-expressed with the MAPKKK genes. Furthermore, a quantitative real-time PCR (qRT-PCR) analysis was performed to assess the relative expression levels of MAPKKKs. Correlation analysis revealed that there was a significant correlation between expression levels of two MAPKKKs and relative biomass responsive to drought in 8 inbred lines. Our results indicate that MAPKKKs may have important regulatory functions in drought tolerance in maize. |
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