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To identify genes involved in the pollen development and maturation, genome-wide transcriptional profiling of the flower buds from fertile and sterile plants of the genic male sterile–fertile line 114AB of Capsicum annuum was performed by the RNA-Seq approach. The results indicated that there were numerous changes in gene expression due to the gene mutation in sterile plants. A total of 668 differential expressed genes were identified. Among them, 562 were up-regulated and 106 were down-regulated genes in the fertile plants compared to those of the sterile plants, including 202 and 2 genes specifically accumulated in fertile and sterile plants, respectively. Hundreds of genes potentially involved in pollen development were identified from the genes specifically expressed in the fertile plants, including pollen coat protein, lipid binding protein, lipid transfer protein, pectin methylesterase, male sterility-related protein, anther-specific protein, pectate lyase gene and so forth. Subsequent analysis of expression patterns for a subset of these genes were verified by semi-quantitative RT-PCR and quantitative RT-PCR. Furthermore, the up-regulated genes were predicted to be associated with intracellular membrane-bounded organelle, cytoplasmic vesicle, oxidoreductase activity, metal ion binding, pollen wall assembly, pollen exine formation, starch and sucrose metabolism, and other processes through Gene ontology and KEGG enrichment analysis. Taken together, this study provides a list of candidate genes and their expression patterns for pollen development and maturation in pepper.

Improvement of biotic and abiotic stress tolerance without yield decrease has been a great challenge in vegetable breeding. Functional stacking of multiple resistant genes could potentially be an effective strategy against more different stress. Here, we report that constitutive co-expression of Arabidopsis thaliana homodomain-leucine zipper transcription factor Enhanced Drought Tolerance/HOMEODOMAIN GLABROUS11 (AtEDT1/HDG11) and Bacillus thuringiensis Cry2Aa2 was able to increase pepper drought tolerance and insect resistance. More importantly, fruit yield was improved under both normal and drought stress conditions. The improved tolerance to drought stress was associated with improved root system and reduced stomatal density. Compared to the non-transgenic control, the transgenic pepper plants also had higher levels of chlorophyll content, chlorophyll fluorescence (Fm/Fv), proline, soluble sugar, abscisic acid, and ROS scavenging capacity under dehydration stress conditions. The increased flower number, elevated fruit weight, and improved fruit number all contributed to the increased yield of transgenic pepper. In addition, bioassays showed that the transgenic plants were effective to control the Prodenia litura, producing a mortality rate of 81.3 % after 5 days of infection. Therefore, our study indicates that stacking of AtEDT1/HDG11 and Cry2Aa2 in pepper plants can improve drought tolerance and insect resistance, demonstrating application of AtEDT1/HDG11 and Cry2Aa2 has the potential to enhance drought tolerance and insect resistance.

Capsaicinoids, metabolites produced in plant placental (seed-bearing) tissue, are responsible for the pungent taste associated with fruits of the genus Capsicum. To identify genes involved in the biosynthesis of capsaicinoids, genome-wide transcriptional profiling of the placenta and pericarp of pungent pepper (C. frutescens L.) was performed using the RNA sequencing (RNA-Seq) approach. The results revealed 4,092 genes with significantly different expression levels between the placenta and pericarp libraries. Among them, 2,049 genes were up-regulated and 2,043 genes were down-regulated in the placenta compared to those of the pericarp. Hundreds of genes potentially regulating capsaicinoid were identified from the up-regulated genes, including genes previously associated with this metabolic process. Subsequent analysis of expression patterns for a subset of these identified genes were verified by semi-quantitative RT-PCR and quantitative RT-PCR. Furthermore, The differential expressed genes were predicted to be involved in microbody, peroxisome, fatty-acid synthase activity, CoA-ligase activity, acyltransferase activity, transaminase activity, phenylalanine metabolism, and other processes through gene ontology and KEGG enrichment analysis. Together, this study provides novel insights into the molecular mechanisms of capsaicinoid biosynthesis.

The translationally controlled tumor protein (TCTP) is an important component of the target of rapamycin (TOR) signaling pathway, the major regulator of cell growth in animals and fungi. Despite its relevance, knowledge on plant TCTP homologs is still limited. In the present study, the full-length BoTCTP cDNA was isolated from a cabbage (Brassica oleracea L.) cDNA library. The BoTCTP cDNA encodes a polypeptide of 168 amino acids and shared the highly conserved GTPase binding surface in all of the species analyzed. Northern blotting analysis showed that BoTCTP was specifically expressed in the root and stem. Furthermore, the expression of BoTCTP could be obviously enhanced by stress stimuli, including high temperature and salt stresses, while no significant changes in the BoTCTP expression were observed under ABA stress. Functional analysis of BoTCTP was performed by the silencing of BoTCTP using RNA interference (RNAi) and the BoTCTP RNAi plants exhibited reduced vegetative growth rate and decreased tolerance of the cold, high temperature, and salt stresses. The reported results clearly suggest that the BoTCTP gene is involved in the regulation of both growth and stress response in cabbage.