DAR2 acts as an important node connecting cytokinin, auxin, SHY2 and PLT1/2 in root meristem size control

Bismuth Vanadium Oxide Can Promote Growth and Activity in Arabidopsis thaliana

The excellent properties of nanomaterials have been confirmed in many fields, but their effects on plants are still unclear. In this study, different concentrations of bismuth vanadate (BV) were added to the growth medium to analyze the growth of seedlings, including taproots, lateral roots, leaf stomata, root activity, and superoxide anion O₂^.- generation. Gene expression levels related to root growth were determined by quantitative PCR in Arabidopsis thaliana. The results showed that BV promoted the growth of taproots and the development of lateral roots, enhanced the length of the extension zone in roots, increased the number and size of leaf stomata and root activity, reduced the accumulation of ROS in seedlings, and changed the expression levels of genes related to polyamines or hormones. At the same time, we investigated the antibacterial activity of BV against a variety of common pathogens causing crop diseases. The results showed that BV could effectively inhibit the growth of Fusarium wilt of cotton and rice sheath blight. These results provide a new prospect for the development of nanomaterial-assisted plants, which is expected to become one of the ways to solve the problem of controlling and promoting the development of plants. At the same time, it also provides a reference for the study of the effect of BV on plants.

Regulation of growth in peach roots by exogenous hydrogen sulfide based on RNA-Seq

Hydrogen sulfide (H₂S) has been shown to regulate many physiological processes of plants. In this study, we observed that 0.2 mM sodium hydrosulfide (NaHS), a donor of H₂S, can regulate the root architecture of peach seedlings, increasing the number of lateral roots by 40.63%. To investigate the specific mechanisms by which H₂S regulates root growth in peach, we used RNA sequencing and heterologous expression technology. Our results showed that exogenous H₂S led to a 44.50% increase in the concentration of endogenous auxin. Analyses of differentially expressed genes (DEGs) revealed that 963 and 1113 genes responded to H₂S on days one and five of treatment, respectively. Among the DEGs, 26 genes were involved in auxin biosynthesis, transport, and signal transduction. Using weighted correlation network analysis, we found that the auxin-related genes in the H₂S-specific gene module were disproportionately involved in polar transport, which may play an important role in H₂S-induced root growth. In addition, we observed that the expression of LATERAL ORGAN BOUNDARIES DOMAIN 16 (PpLBD16) was significantly up-regulated by exogenous application of H₂S in peach. Overexpression of PpLBD16 in an Arabidopsis system yielded a 66.83% increase in the number of lateral roots. Under exposure to exogenous H₂S, there was also increased expression of genes related to cell proliferation, indicating that H₂S regulates the growth of peach roots. Our work represents the first comprehensive transcriptomic analysis of the effects of exogenous application of H₂S on the roots of peach, and provides new insights into the mechanisms underlying H₂S-induced root growth.

Transcriptome Profiling of Tiller Buds Provides New Insights into PhyB Regulation of Tillering and Indeterminate Growth in Sorghum

Phytochrome B (phyB) enables plants to modify shoot branching or tillering in response to varying light intensities and ratios of red and far-red light caused by shading and neighbor proximity. Tillering is inhibited in sorghum genotypes that lack phytochrome B (58M, phyB-1) until after floral initiation. The growth of tiller buds in the first leaf axil of wild-type (100M, PHYB) and phyB-1 sorghum genotypes is similar until 6 d after planting when buds of phyB-1 arrest growth, while wild-type buds continue growing and develop into tillers. Transcriptome analysis at this early stage of bud development identified numerous genes that were up to 50-fold differentially expressed in wild-type/phyB-1 buds. Up-regulation of terminal flower1, GA2oxidase, and TPPI could protect axillary meristems in phyB-1 from precocious floral induction and decrease bud sensitivity to sugar signals. After bud growth arrest in phyB-1, expression of dormancy-associated genes such as DRM1, GT1, AF1, and CKX1 increased and ENOD93, ACCoxidase, ARR3/6/9, CGA1, and SHY2 decreased. Continued bud outgrowth in wild-type was correlated with increased expression of genes encoding a SWEET transporter and cell wall invertases. The SWEET transporter may facilitate Suc unloading from the phloem to the apoplast where cell wall invertases generate monosaccharides for uptake and utilization to sustain bud outgrowth. Elevated expression of these genes was correlated with higher levels of cytokinin/sugar signaling in growing buds of wild-type plants.

AIL and HDG proteins act antagonistically to control cell proliferation

Aintegumenta-like (AIL) transcription factors are key regulators of cell proliferation and meristem identity. Although AIL functions have been well described, the direct signalling components of this pathway are largely unknown. We show that baby boom (BBM) and other AIL proteins physically interact with multiple members of the L1-expressed homeodomain glabrous (HDG) transcription factor family, including HDG1, HDG11 and HDG12. Overexpression of HDG1, HDG11 and HDG12 restricts growth due to root and shoot meristem arrest, which is associated with reduced expression of genes involved in meristem development and cell proliferation pathways, whereas downregulation of multiple HDG genes promotes cell overproliferation. These results suggest a role for HDG proteins in promoting cell differentiation. We also reveal a transcriptional network in which BBM and HDG1 regulate several common target genes, and where BBM/AIL and HDG regulate the expression of each other. Taken together, these results suggest opposite roles for AIL and HDG proteins, with AILs promoting cell proliferation and HDGs stimulating cell differentiation, and that these functions are mediated at both the protein-protein interaction and transcriptional level.