Artificial microRNA-based gene silencing approach in PM-susceptible Vitis vinifera cv to stably silence the 'Chardonnay' ortholog of AtPMR6, VvPLL3 improves foliar resistance against the PM fungus.
A miR166a-MpATHB8-MpMYB10b regulatory module that enhances rust resistance through anthocyanin metabolism in M. ‘Profusion’ provides novel insights into the miRNA-mediated regulation of anthocyanin metabolism and facilitate the breeding of rust-resistant and anthocyanin-enriched Malus cultivars.
It is demonstrated that CmVQ23 functions as a positive regulator of resistance to Verticillium dahliae by orchestrating ROS/HR-mediated cell death, antioxidant defense, phenylpropanoid pathway activation, and phytohormone signaling crosstalk, offering a promising genetic resource for improving Verticillium wilt resistance in crops.
To defend against pathogen invasion, plants deploy a variety of strategies, among which salicylic acid (SA), a key plant defense hormone, plays crucial roles in enhancing host resistance to biotrophic and semibiotrophic microbes. Although numerous studies elucidated mechanisms of the SA signaling pathway, many questions remain. In this study, we show that the group IIc WRKY transcription factor VvWRKY8 is involved in grape (Vitis vinifera) defense responses to the oomycete pathogen Plasmopara viticola, as indicated by transcriptome analyses. VvWRKY8 increases the expression of defense-related genes and SA accumulation, thereby promoting grape resistance to P. viticola. Further analyses reveal that VvWRKY8 is recruited to the promoters of VvCBP60g and VvSARD1, which encode two key regulators of SA biosynthesis, and upregulates their transcription. Moreover, VvWRKY8 transcription is induced by SA and by two bZIP transcription factors, VvTGA2a and VvTGA2b, which cooperate with the SA receptors VvNPR1 and VvNPR3 to modulate the expression of SA-responsive genes. Collectively, our results indicate that a positive feedback loop involving VvWRKY8 and the SA pathway components VvCBP60g, VvSARD1, and VvTGA2a/2b functions in response to P. viticola attack in grapevine.
Huimin Huang, Jun-Jie Qu, Jiaqi Liu et al.· Molecular Horticulture· 0 citations
StERF87 directly activates StPR1a via GCC-box binding and integrates SA/ET signaling to enhance bacterial wilt resistance. Potato (Solanum tuberosum) is an important food crop worldwide, yet its yield is severely constrained by bacterial wilt caused by Ralstonia solanacearum. We used RNA-Seq to study gene expression in ‘Z1076-1’ at 0, 1, and 2 days post-inoculation (dpi) with R. solanacearum (10⁶ CFU mL⁻1). We identified 6663 differentially expressed genes at 1 dpi and 7390 at 2 dpi. Calcium signaling and MAPK cascade genes were upregulated at 1 dpi. PR protein and ROS-related genes showed stronger induction at 2 dpi. The ethylene-responsive transcription factor StERF87 was continuously upregulated. Its expression increased 4.7-fold at 2 dpi, with FPKM values over 100. We selected this gene for functional analysis. Transgenic potato plants overexpressing StERF87 showed lower disease severity and reduced bacterial growth in both whole plants and tuber slices. StERF87 is a transcriptional activator that directly binds the GCC-box in the StPR1a promoter to activate its transcription. After R. solanacearum inoculation, StERF87 overexpression also increased PR1b1 expression, elevated salicylic acid and ethylene levels, reduced jasmonic acid accumulation, and altered the activities of ROS-scavenging enzymes including SOD, POD, and CAT. These results show that StERF87 regulates potato defense against R. solanacearum and may be useful for breeding bacterial wilt-resistant varieties.
Ru Yu, Min Gao, Lin Cai et al.· Plant Cell Reports· 0 citations
Plant cell walls serve as a physical support and a barrier to pathogen invasion. Cellulose is the main component of cell walls. The cellulose synthase-like D (CSLD) subfamily genes are required for plant normal development. In rice, Oscsld4 mutant plants are dwarfed and have narrow, rolled leaves. The role of OsCSLD4 in rice immune responses is unclear. We carried out a forward genetic screen using rice mutants expressing the XA21 immune receptor to identify components required for the resistance to Xanthomonas oryzae pv. oryzae (Xoo). One mutant from the screen carries a loss-of-function mutation in OsCSLD4. OsCSLD4 is required for resistance to Xoo mediated by both the XA21 and XA26 immune receptors and also participates in the basal resistance to Xoo. Hallmarks of the XA21-mediated immune response, including induction of the defense marker gene KO5, reactive oxygen species (ROS) burst and the phosphorylation of mitogen-activated protein kinases (MAPKs), are not compromised in the Oscsld4 mutant. These findings suggest that OsCSLD4 does not function as a core signaling component of the immune receptor pathway, but rather maintains the structural integrity of the cell wall as an effective physical barrier. This structural defense is essential for the full manifestation of both innate and receptor-mediated immunity.
Accumulation of silicon (Si) is known to confer resistance in plants against abiotic and biotic stresses; however, questions remain about the underlying mechanisms of Si-mediated resistance against insect herbivores. We investigated the Si-mediated resistance mechanisms in rice against fall armyworm,
Spodoptera frugiperda,
using the
OsLsi1
mutant rice (cv. Nipponbare) lines deficient in Si uptake from the soil.
We investigated these questions using a multidisciplinary approach, combining bioassays of insect and plant growth and biochemical quantification of defense metabolites, phytohormones, and volatiles. Further, we studied constitutive and herbivory-induced gene expression in Os
Lsi1
rice mutants relative to the wild type (WT). Moreover, we detected high-impact SNPs/InDels associated with plant–insect interactions, and integrated these variants with expression signatures across mutants and WT.
Si played a key role in mediating constitutive resistance to FAW, but Si content did not substantially alter induced responses. High Si content promoted compensatory growth post-herbivory and had no effect on constitutive or induced activities of peroxidases, polyphenol oxidases, trypsin inhibitors, and jasmonic acid. Low Si plants constitutively emitted higher levels of certain terpene volatiles. Comparative transcriptomics across mutants and WT showed that Si modulates gene expression under both constitutive and post-herbivory. Plants with high Si levels appear well defended but also capable of allocating resources to re-growth than low Si plants. Genes including
OsbHLH024, OsLsi1, OsMSH3
,
OsARC5, OsCKX2
, and
OsBBX3
are candidates for engineering rice varieties with enhanced herbivory resistance.
These results suggest that Si-deficient rice lines are genetically and transcriptionally less equipped to resistance.
J. Sharma, Chanderkant Chaudhary, Rajat Pruthi et al.· Plant and Soil· 0 citations
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