ABSTRACT
Calcium signaling plays a critical role in response to various abiotic and biotic stresses in plants. Preliminarily evidence showed that calcium signaling perceived and transduced the harmful signaling generated from continuous cropping stress in R. glutinosa. To investigate the roles of calcium signaling in continuous cropping injury formation, the key genes involved in calcium signaling transduction were identified in R. glutinosa transcriptome through bioinformatic methods. Furthermore, the calcium ion concentration in both normal and continuous cropping R. glutinosa root cells were measured by potassium pyroantimonate precipitation and calcium fluorescence method. As a result, a set of 84 calcium signaling-related genes, including 5 CaMs, 12 CBLs, 21 CDPKs, 21 CIPKs, 16 CMLs, and 9 CRKs were captured in R. glutinosa transcriptome. The analysis of expression profile in continuous cropping compared to normal growth R. glutinosa indicated that continuous cropping stress significantly increased the expression of calcium signaling-related genes in continuous cropping R. glutinosa. At the same time, the abundance levels of 12 calcium signaling-related genes quantified by qPCR further validated the high expression of calcium signaling-related genes presented in continous cropping R. glutinosa. In addition, the continuous cropping condition significantly promoted the accumulation of intracellular calcium ions in R. glutinosa based on two methods of potassium pyroantimonate precipitation and calcium fluorescence. This study verified the possible roles of calcium signaling in the formation of continuous cropping injury on molecular and cellular level, which lays a solid foundation for illuminating formation mechanism of continuous cropping injury on molecular level.