Abstract
BackgroundThe pepper fruit is the second most consumed vegetable worldwide. However, low temperature affects the vegetative development and reproduction of the pepper, resulting in economic losses. To identify cold-related genes regulated by abscisic acid (ABA) in pepper seedlings, cDNA representational difference analysis was previously performed using a suppression subtractive hybridization method. One of the genes cloned from the subtraction was homologous to Solanum tuberosum MBF1 (StMBF1) encoding the coactivator multiprotein bridging factor 1. Here, we have characterized this StMBF1 homolog (named CaMBF1) from Capsicum annuum and investigated its role in abiotic stress tolerance.ResultsTissue expression profile analysis using quantitative RT-PCR showed that CaMBF1 was expressed in all tested tissues, and high-level expression was detected in the flowers and seeds. The expression of CaMBF1 in pepper seedlings was dramatically suppressed by exogenously supplied salicylic acid, high salt, osmotic and heavy metal stresses. Constitutive overexpression of CaMBF1 in Arabidopsis aggravated the visible symptoms of leaf damage and the electrolyte leakage of cell damage caused by cold stress in seedlings. Furthermore, the expression of RD29A, ERD15, KIN1, and RD22 in the transgenic plants was lower than that in the wild-type plants. On the other hand, seed germination, cotyledon greening and lateral root formation were more severely influenced by salt stress in transgenic lines compared with wild-type plants, indicating that CaMBF1-overexpressing Arabidopsis plants were hypersensitive to salt stress.ConclusionsOverexpression of CaMBF1 in Arabidopsis displayed reduced tolerance to cold and high salt stress during seed germination and post-germination stages. CaMBF1 transgenic Arabidopsis may reduce stress tolerance by downregulating stress-responsive genes to aggravate the leaf damage caused by cold stress. CaMBF1 may be useful for genetic engineering of novel pepper cultivars in the future.
Highlights
The pepper fruit is the second most consumed vegetable worldwide
CaMBF1 transgenic Arabidopsis may reduce stress tolerance by downregulating stress-responsive genes to aggravate the leaf damage caused by cold stress
CaMBF1 may be useful for genetic engineering of novel pepper cultivars in the future
Summary
The pepper fruit is the second most consumed vegetable worldwide. low temperature affects the vegetative development and reproduction of the pepper, resulting in economic losses. Transcriptional regulatory proteins play a central role in the expression of genomic information during complex biological processes in all organisms. Direct evidence of the involvement of MBF1 in plant responses to environmental stresses was obtained by enhancing tolerance to heat and osmotic stresses in transgenic Arabidopsis lines expressing the AtMBF1c gene and more recently AtMBF1a, without growth retardation [9,10]. These data indicate that MBF1-like genes can be associated with a variety of developmental processes in plants such as environmental stress tolerance. There are very few data on the significance of MBF1 in cold stress tolerance
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