Plant Signaling & Behavior最新文献

The small regulatory C-TERMINALLY ENCODED PEPTIDE (CEP) peptide family plays crucial roles in plant growth and stress response. However, little is known about this peptide family in Brassica species. Here, we performed a systematic analysis to identify the putative Brassica rapa L. CEP (BrCEP) gene family. In total, 27 BrCEP genes were identified and they were classified into four subgroups based on the CEP motifs similarity. BrCEP genes displayed distinct expression patterns in response to both developmental and several environmental signals, suggesting their broad roles during Brassica rapa development. Furthuremore, the synthetic BrCEP3 peptide accelerated Brassica rapa primary root growth in a hydrogen peroxide (H₂O₂) and Ca²⁺ dependent manner. In summary, our work will provide fundamental insights into the physiological function of CEP peptides during Brassica rapa development.

Platycodon grandiflorus, a perennial flowering plant widely distributed in China and South Korea, is an excellent resource for both food and medicine. The main active compounds of P. grandiflorus are triterpenoid saponins. WRKY transcription factors (TFs) are among the largest gene families in plants and play an important role in regulating plant terpenoid accumulation, physiological metabolism, and stress response. Numerous studies have been reported on other medicinal plants; however, little is known about WRKY genes in P. grandiflorus. In this study, 27 PgWRKYs were identified in the P. grandiflorus transcriptome. Phylogenetic analysis showed that PgWRKY genes were clustered into three main groups and five subgroups. Transcriptome analysis showed that the PgWRKY gene expression patterns in different tissues differed between those in Tongcheng City (Southern Anhui) and Taihe County (Northern Anhui). Gene expression analysis based on RNA sequencing and qRT-PCR analysis showed that most PgWRKY genes were expressed after induction with methyl jasmonate (MeJA). Co-expressing PgWRKY genes with triterpenoid biosynthesis pathway genes revealed four PgWRKY genes that may have functions in triterpenoid biosynthesis. Additionally, functional annotation and protein-protein interaction analysis of PgWRKY proteins were performed to predict their roles in potential regulatory networks. Thus, we systematically analyzed the structure, evolution, and expression patterns of PgWRKY genes to provide an important theoretical basis for further exploring the molecular basis and regulatory mechanism of WRKY TFs in triterpenoid biosynthesis.

Piriformospora indica is a root endophyte having a vast host range in plants. Plant growth promotion is a hallmark of the symbiotic interaction of P. indica with its hosts. As a plant growth-promoting microorganism, it is important to know the mechanisms involved in growth induction. Hitherto, multiple reports have demonstrated various molecular mechanisms of P. indica-mediated growth promotion, including protein kinase-mediated pathway, enhanced nutrient uptake and polyamine-mediated growth phytohormone elevation. Here, we briefly present a discussion on the state-of-the-art molecular mechanisms of P. indica-mediated growth promotion in host plants, in order to obtain a future prospect on utilization of this microorganism for sustainable agriculture.

Belowground plant-plant interactions can affect the concentrations of leaf chemicals, but the mechanism is not clear. Here, we investigated the effects of intra- and interspecific root exudates on the growth and leaf chemical content of Rumex obtusifolius. Seedlings of R. obtusifolius were grown with exposure to root exudates collected from other R. obtusifolius plants or from Trifolium repens, Festuca ovina, or Plantago asiatica plants, and the total phenolic, condensed tannin, dry biomass, and chlorophyll contents of the leaves were examined. The root exudates from conspecific plants had no effect on the total phenolic, condensed tannin, and chlorophyll contents of the leaves but did significantly reduce the dry leaf biomass. Root exudates from heterospecific plants had different effects depending on the species. These results were different from the results of a previous study that examined the effects of direct plant-plant interaction in R. obtusifolius. Thus, indirect interaction via root exudates induces different effects in leaves from direct interaction.

BT4 gene was identified to play an important role in Arabidopsis resistance to pst DC3000 in preliminary studies. However, the specific function and molecular mechanism of BT4 gene in regulation of Arabidopsis resistance to Botrytis cinerea had not been described to date. In this study, we found that the expression of BT4 was induced by wounding and B. cinerea inoculation in Arabidopsis. After inoculated with B. cinerea, T-DNA insertion mutants of the BT4 gene, bt4, showed significant susceptibility symptoms, whereas no significant symptoms were found in wild-type (WT), the complemented transgenic plants (CE), and the overexpression transgenic plants (OE). After inoculated with B. cinerea, the expression levels of JAR1 and PDF1.2 genes in bt4 mutant were induced; however, the expression levels of these genes in bt4 mutant were significantly lower than those in the WT, CE, and OE. These results indicated that the BT4 positively regulate the expression of genes in JA/ET signaling pathways. Therefore, the BT4 may be involved in the regulation of JA/ET signaling pathways to affect Arabidopsis resistance to B. cinerea.

Brassinosteroids (BRs) regulate of maize (Zea mays L.) growth, but the underlying molecular mechanism remains unclear. In this study, we used a multi-disciplinary approach to determine how BRs regulate maize morphology and physiology during development. Treatment with the BRs promoted primary root the elongation and growth during germination, and the early development of lateral roots. BRs treatment during the middle growth stage increased the levels of various stress resistance factors, and enhanced resistance to lodging, likely by protecting the plant against stem rot and sheath rot. BRs had no significant effect on plant height during late growth, but it increased leaf angle and photosynthetic efficiency, as well as yield and quality traits. Our findings increase our understanding of the regulatory effects of BR on maize root growth and development and the mechanism by which BR improves disease resistance, which could further the potential for using BR to improve maize yield.

Plant glutamate receptor homologs (GLRs), which function as key calcium channels, play pivotal roles in various developmental processes as well as stress responses. The moss Physcomitrium patens, a representative of the earliest land plant lineage, possess multiple pathways of hormone signaling for coordinating growth and adaptation responses. However, it is not clear whether GLRs are connected to hormone-mediated growth control in the moss. In this study, we report that one of the two GLRs in P. patens, PpGLR1, involves in abscisic acid (ABA)-mediated growth regulation. ABA represses the growth of wild-type moss, and intriguingly, the PpGLR1 transcript levels are significantly increased in response to ABA treatment, based on both gene expression and the PpGLR1pro::GUS reporter results. Furthermore, the growth of Ppglr1 knockout moss mutants is hypersensitive to ABA treatment. These results suggest that PpGLR1 plays a critical role in ABA-mediated growth regulation, which provide useful information for our further investigation of the regulatory mechanism between Ca²⁺ signal and ABA in moss growth control.

The δ-aminolevulinic acid dehydratase (ALAD) enzyme is an intermediate in the biosynthetic pathway of tetrapyrroles. It combines two δ-aminolevulinic acid (δ-ALA) molecules to form the pyrrole, porphobilinogen, an important precursor for plant pigments involved in photosynthesis, respiration, light-sensing, and nutrient uptake. Our recent efforts showed that, in citrus, silencing of ALAD gene via Citrus tristeza virus-induced gene silencing, caused yellow spots and necrosis in leaves and in developing new shoots. Silencing of ALAD gene reduced leaf pigments and altered leaf metabolites. Moreover, total phenolic content, H₂O_2, and reactive oxygen species (ROS) increased, indicating that silencing of ALAD induced severe stress. Herein, we hypothesized that conditions including lower sucrose, elevated ROS, alteration of microRNA involved in RNAi regulatory protein Argonaute 1 (AGO1) and ROS lead to higher deposition of callose in phloem tissues. Using aniline blue staining and gene expression analysis of callose synthases, we showed significant deposition of callose in ALAD-silenced citrus.

DEK is associated with DNA replication and break repair, mRNA splicing, and transcriptional regulation, which had been studied in humans and mammals. The function of DEK in plants was poorly understood. In this study, GhDEK2D was identified in Gossypium hirsutum by genome-wide and post-translational modifications. GhDEK2D had been phosphorylated, acetylated and ubiquitylated under Verticillium dahliae (Vd) challenge. The GhDEK2D-silenced cotton decreased resistance against Vd. In GhDEK2D-silenced cotton plants, the reactive oxygen species was activated, the callose, xylogen, hypersensitive reaction (HR) and expression levels of defense-related genes were reduced. Homozygous overexpressing-GhDEK2D transgenic Arabidopsis lines were more resistant to Verticillium wilt (Vw). We propose that GhDEK2D was a potential molecular target for improving resistance to Vw in cotton.

Elevated CO₂ (eCO₂; 1000 ppm) influences developing rice leaf formation, reducing leaf blade length and width as compared to rice grown under ambient CO₂ (aCO₂; 400 ppm). Since micro RNAs (miRNAs) are known to play multiple roles in plant development, we hypothesized that miRNAs might be involved in modulating leaf size under eCO₂ conditions. To identify miRNAs responding to eCO₂, we profiled miRNA levels in developing rice leaves (P4; plastochron number of the fourth-youngest leaf) under eCO₂ using small RNA-seq. We detected 18 mature miRNA sequences for which expression levels varied more than two-fold between the eCO₂ and aCO₂ conditions. Among them, only miR396e and miR396f significantly differed between the two conditions. Additionally, the expression of growth-regulating factors (GRFs), potential target mRNA of miR396s, were repressed under the eCO₂ condition. We used an antisense oligonucleotide approach to confirm that single-strand DNA corresponding to the miR396e sequence effectively downregulated GRF expression in developing leaves, reducing the leaf blade length, such as for rice grown under eCO₂. These results suggest that the miR396-GRF module is crucially relevant to controlling rice leaf blade length in eCO₂ environments.