Root Adaptive Responses to Aluminum-Treatment Revealed by RNA-Seq in Two Citrus Species With Different Aluminum-Tolerance.
Seedlings of aluminum (Al)-tolerantCitrus sinensisand Al-intolerantCitrus grandiswere fertigated daily with nutrient solution containing 0 and 1.0 mM AlCl3●6H2O for 18 weeks. The Al-induced decreases of biomass and root total soluble proteins only occurred inC. grandis, demonstrating thatC. sinensishad higher Al-tolerance thanC. grandis. Under Al-treatment,C. sinensisroots secreted more citrate and malate thanC. grandisones; less Al was accumulated inC. sinenisthan inC. grandisleaves. The Al-induced reduction of phosphorus was lesser inC. sinensisroots and leaves than inC. grandisones, whereas the Al-induced increase of sulfur was greater inC. sinensisroots and leaves. Using RNA-seq, we isolated 1905 and 2670 differentially expressed genes (DEGs) from Al-treatedC. sinensisthanC. grandisroots, respectively. Among these DEGs, only 649 DEGs were shared by the two species. Further analysis suggested that the following several aspects conferredC. sinensishigher Al-tolerance: (a) Al-treatedC. sinensisseedlings had a higher external Al detoxification capacityviaenhanced Al-induced secretion of organic acid anions, a higher antioxidant capacity and a more efficient chelation system in roots; (b) Al-treatedC. sinensisseedlings displayed a higher level of sulfur in roots and leaves possibly due to increased uptake and decreased export of sulfur and a higher capacity to maintain the cellular phosphorus homeostasis by enhancing phosphorus acquisition and utilization; (c) Cell wall and cytoskeleton metabolism, energy and carbohydrate metabolism and signal transduction displayed higher adaptative responses to Al inC. sinensisthan inC. grandisroots; (d) More upregulated than downregulated genes related to fatty acid and amino acid metabolisms were isolated from Al-treatedC. sinensisroots, but the reverse was the case for Al-treatedC. grandisroots. These results provide a platform for further investigating the roles of genes possibly responsible for citrus Al-tolerance.
Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry University Fuzhou, China.
Peng
P
Guo
Institute of Materia Medica, Fujian Academy of Medical Sciences Fuzhou, China.
Yi-Ping
YP
Qi
Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry University Fuzhou, China.
Lin-Tong
LT
Yang
Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry University Fuzhou, China.
Ning-Wei
NW
Lai
Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry University Fuzhou, China.
Xin
X
Ye
Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry University Fuzhou, China.
Yi
Y
Yang
Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry UniversityFuzhou, China; Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry UniversityFuzhou, China; The Higher Educational Key Laboratory of Fujian Province for Soil Ecosystem Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry UniversityFuzhou, China.
Li-Song
LS
Chen
Citrus grandis; Citrus sinensis; RNA-Seq; aluminum; organic acid anion secretion; phosphorus homeostasis; sulfur metabolism