The Phosphate Transporter1 (PHT1) family of genes plays pivotal roles in the uptake of inorganic phosphate from soils. However, there is no comprehensive report on the PHT1 family in Zea mays based on the whole genome. In the present study, a total of 13 putative PHT1 genes (ZmPHT1;1 to 13) were identified in the inbred line B73 genome by bioinformatics methods. Then, their function was investigated by a yeast PHO84 mutant complementary experiment and qRT-PCR. Thirteen ZmPHT1 genes distributed on six chromosomes (1, 2, 5, 7, 8 and 10) were divided into two paralogues (Class A and Class B). ZmPHT1;1/ZmPHT1;9 and ZmPHT1;9/ZmPHT1;13 are produced from recent segmental duplication events. ZmPHT1;1/ZmPHT1;13 and ZmPHT1;8/ZmPHT1;10 are produced from early segmental duplication events. All 13 putative ZmPHT1s can completely or partly complement the yeast Pi-uptake mutant, and they were obviously induced in maize under low Pi conditions, except for ZmPHT1;1 (p < 0.01), indicating that the overwhelming majority of ZmPHT1 genes can respond to a low Pi condition. ZmPHT1;2, ZmPHT1;4, ZmPHT1;6, ZmPHT1;7, ZmPHT1;9 and ZmPHT1;11 were up-regulated by arbuscular mycorrhizal fungi (AMF), implying that these genes might participate in mediating Pi absorption and/or transport. Analysis of the promoters revealed that the MYCS and P1BS element are widely distributed on the region of different AMF-inducible ZmPHT1 promoters. In light of the above results, five of 13 ZmPHT1 genes were newly-identified AMF-inducible high-affinity phosphate transporters in the maize genome. Our results will lay a foundation for better understanding the PHT1 family evolution and the molecular mechanisms of inorganic phosphate transport under AMF inoculation.

Alternative splicing (AS) is a post-transcriptional level of gene expression regulation that increases transcriptome and proteome diversity. How the AS landscape of rapeseed (Brassica napus L.) changes in response to the fungal pathogen Sclerotinia sclerotiorum is unknown. Here, we analyzed 18 RNA-seq libraries of mock-inoculated and S. sclerotiorum-inoculated susceptible and tolerant B. napus plants. We found that infection increased AS, with intron retention being the main AS event. To determine the key genes functioning in the AS response, we performed a differential AS (DAS) analysis. We identified 79 DAS genes, including those encoding splicing factors, defense response proteins, crucial transcription factors and enzymes. We generated coexpression networks based on the splicing isoforms, rather than the genes, to explore the genes’ diverse functions. Using this weighted gene coexpression network analysis alongside a gene ontology enrichment analysis, we identified 11 modules putatively involved in the pathogen defense response. Within these regulatory modules, six DAS genes (ascorbate peroxidase 1, ser/arg-rich protein 34a, unknown function 1138, nitrilase 2, v-atpase f, and amino acid transporter 1) were considered to encode key isoforms involved in the defense response. This study provides insight into the post-transcriptional response of B. napus to S. sclerotiorum infection.

HD-Zip III transcription factors are known to play roles in regulating shoot apical meristem (SAM) and axillary meristem (AM) development, exerting direct effects on plant architecture and branching. However, the HD-Zip III (BjuHDZ) gene family has not been systematically characterized in Brassica juncea L. (B. juncea). Therefore, in this study, we performed a comprehensive bioinformatics analysis of the BjuHDZ gene family and identified a total of 20 members. These genes were randomly and unevenly distributed across the 16 chromosomes of B. juncea, and their encoded proteins exhibited divergent physicochemical properties. Through phylogenetic analysis, the 20 BjuHDZ proteins were divided into five subgroups (REV, HB8, HB9, HB14, and HB15). Conserved exon–intron organization and motif profiles were observed within each BjuHDZ gene subgroup. Furthermore, their promoter sequences harbored a wide array of cis-elements implicated in light responsiveness, hormonal regulation, stress tolerance, and growth/development. The qRT-PCR analysis showed that the expression levels of BjuHDZ7, BjuHDZ13, and BjuHDZ15 were significantly upregulated in the middle and upper axillary buds of two pairs of multi-branching (Bj02 and, Bj08) accessions. Meanwhile, BjuHDZ17 was highly expressed in the upper, middle, and lower axillary buds as well as in the SAM of both multi-branching materials. Taken together, these findings lay a foundation for further investigation into the biological functions of BjuHDZ genes in B. juncea.