Caixia Lu

Identification and expression profiling analysis of calmodulin-binding transcription activator genes in maize (Zea mays L.) under abiotic and biotic stresses.

The calmodulin-binding transcription activators (CAMTA) play critical roles in plant growth and responses to environmental stimuli. However, how CAMTAs function in responses to abiotic and biotic stresses in maize (Zea mays L.) is largely unknown. In this study, we first identified all the CAMTA homologous genes in the whole genome of maize. The results showed that nine ZmCAMTA genes showed highly diversified gene structures and tissue-specific expression patterns. Many ZmCAMTA genes displayed high expression levels in the roots. We then surveyed the distribution of stress-related cis-regulatory elements in the −1.5 kb promoter regions of ZmCAMTA genes. Notably, a large number of stress-related elements present in the promoter regions of some ZmCAMTA genes, indicating a genetic basis of stress expression regulation of these genes. Quantitative real-time PCR was used to test the expression of ZmCAMTA genes under several abiotic stresses (drought, salt, and cold), various stress-related hormones [abscisic acid, auxin, salicylic acid (SA), and jasmonic acid] and biotic stress [rice black-streaked dwarf virus (RBSDV) infection]. Furthermore, the expression pattern of ZmCAMTA genes under RBSDV infection was analyzed to investigate their potential roles in responses of different maize cultivated varieties to RBSDV. The expression of most ZmCAMTA genes responded to both abiotic and biotic stresses. The data will help us to understand the roles of CAMTA-mediated Ca2+ signaling in maize tolerance to environmental stresses.

Transcriptome Analysis of Cadmium-Treated Roots in Maize (Zea mays L.)

Cadmium (Cd) is a heavy metal and is highly toxic to all plant species. However, the underlying molecular mechanism controlling the effects of auxin on the Cd stress response in maize is largely unknown. In this study, the transcriptome produced by maize ‘Zheng 58’ root responses to Cd stress was sequenced using Illumina sequencing technology. In our study, six RNA-seq libraries yielded a total of 244 million clean short reads and 30.37 Gb of sequence data. A total of 6342 differentially expressed genes (DEGs) were grouped into 908 Gene Ontology (GO) categories and 198 Kyoto Encyclopedia of Genes and Genomes terms. GO term enrichment analysis indicated that various auxin signaling pathway-related GO terms were significantly enriched in DEGs. Comparison of the transcript abundances for auxin biosynthesis, transport, and downstream response genes revealed a universal expression response under Cd treatment. Furthermore, our data showed that free indole-3-acetic acid (IAA) levels were significantly reduced; but IAA oxidase activity was up-regulated after Cd treatment in maize roots. The analysis of Cd activity in maize roots under different Cd and auxin conditions confirmed that auxin affected Cd accumulation in maize seedlings. These results will improve our understanding of the complex molecular mechanisms underlying the response to Cd stress in maize roots.

Comparative proteomic analysis of maize (Zea mays L.) seedlings under rice black-streaked dwarf virus infection

BackgroundMaize rough dwarf disease (MRDD) is a severe disease that has been occurring frequently in southern China and many other Asian countries. MRDD is caused by the infection of Rice black streaked dwarf virus (RBSDV) and leads to significant economic losses in maize production. To well understand the destructive effects of RBSDV infection on maize growth, comparative proteomic analyses of maize seedlings under RBSDV infection was performed using an integrated approach involving LC-MS/MS and Tandem Mass Tag (TMT) labeling.ResultsIn total, 7615 maize proteins, 6319 of which were quantified. A total of 116 differentially accumulated proteins (DAPs) were identified, including 35 up- and 81 down-regulated proteins under the RBSDV infection. Enrichment analysis showed that the DAPs were most strongly associated with cyanoamino acid metabolism, protein processing in ER, and ribosome-related pathways. Two sulfur metabolism-related proteins were significantly reduced, indicating that sulfur may participate in the resistance against RBSDV infection. Furthermore, 15 DAPs involved in six metabolic pathways were identified in maize under the RBSDV infection.ConclusionsOur data revealed that the responses of maize to RBSDV infection were controlled by various metabolic pathways.