Overexpression of AcWRKY31 Increases Sensitivity to Salt and Drought and Improves Tolerance to Mealybugs in Pineapple.

Pineapple is a globally significant tropical fruit, but its cultivation faces numerous challenges due to abiotic and biotic stresses, affecting its quality and quantity. WRKY transcription factors are known regulators of stress responses, however, their specific functions in pineapple are not fully understood. This study investigates the role of AcWRKY31 by overexpressing it in pineapple and Arabidopsis. Transgenic pineapple lines were obtained using Agrobacterium-mediated transformation methods and abiotic and biotic stress treatments. Transgenic AcWRKY31-OE pineapple plants showed an increased sensitivity to salt and drought stress and an increased resistance to biotic stress from pineapple mealybugs compared to that of WT plants. Similar experiments in AcWRKY31-OE, AtWRKY53-OE, and the Arabidopsis Atwrky53 mutant were performed and consistently confirmed these findings. A comparative transcriptomic analysis revealed 5357 upregulated genes in AcWRKY31-OE pineapple, with 30 genes related to disease and pathogen response. Notably, 18 of these genes contained a W-box sequence in their promoter region. A KEGG analysis of RNA-Seq data showed that upregulated DEG genes are mostly involved in translation, protein kinases, peptidases and inhibitors, membrane trafficking, folding, sorting, and degradation, while the downregulated genes are involved in metabolism, protein families, signaling, and cellular processes. RT-qPCR assays of selected genes confirmed the transcriptomic results. In summary, the AcWRKY31 gene is promising for the improvement of stress responses in pineapple, and it could be a valuable tool for plant breeders to develop stress-tolerant crops in the future.

Advances in micropropagation, somatic embryogenesis, somatic hybridizations, genetic transformation and cryopreservation for Passiflora improvement.

Passion fruit is an essential commercial plant in the tropics and subtropics, which has lately seen a rise in demand for high-quality fruits and large-scale production. Generally, different species of passion fruit (Passiflora sp.) are propagated by sexual reproduction. However, asexual reproduction, such as stem cuttings, grafting, or tissue culture, is also available and advantageous in many instances. Recent research on passion fruit has concentrated on improving and establishing methodologies for embryogenesis, clonal proliferation via (somatic embryos), homozygote regeneration (by anther culture), germplasm preservation (via cryopreservation), and genetic transformation. These developments have resulted in potentially new directions for asexual propagation. Even though effective embryo culture and cryogenics are now available, however the limited frequency of embryogenic callus transformation to ex-vitro seedlings still restricts the substantial clonal replication of passion fruit. Here, in this review the advancement related to biotechnological approaches and the current understanding of Passiflora tissue culture. In vitro culture, organogenesis, cryopreservation, breeding, and productivity of Passiflora will significantly improve with novel propagation approaches, which could be applied to a wider range of germplasm.

GmbZIP152, a Soybean bZIP Transcription Factor, Confers Multiple Biotic and Abiotic Stress Responses in Plant.

Soybean is one of the most important food crops in the world. However, with the environmental change in recent years, many environmental factors like drought, salinity, heavy metal, and disease seriously affected the growth and development of soybean, causing substantial economic losses. In this study, we screened a bZIP transcription factor gene, GmbZIP152, which is significantly induced by Sclerotinia sclerotiorum (S. sclerotiorum), phytohormones, salt-, drought-, and heavy metal stresses in soybean. We found that overexpression of GmbZIP152 in Arabidopsis (OE-GmbZIP152) enhances the resistance to S. sclerotiorum and the tolerance of salt, drought, and heavy metal stresses compared to wild-type (WT). The antioxidant enzyme related genes (including AtCAT1, AtSOD, and AtPOD1) and their enzyme activities are induced by S. sclerotiorum, salt, drought, and heavy metal stress in OE-GmbZIP152 compared to WT. Furthermore, we also found that the expression level of biotic- and abiotic-related marker genes (AtLOX6, AtACS6, AtERF1, and AtABI2, etc.) were increased in OE-GmbZIP152 compared to WT under S. sclerotiorum and abiotic stresses. Moreover, we performed a Chromatin immunoprecipitation (ChIP) assay and found that GmbZIP152 could directly bind to promoters of ABA-, JA-, ETH-, and SA-induced biotic- and abiotic-related genes in soybean. Altogether, GmbZIP152 plays an essential role in soybean response to biotic and abiotic stresses.

ROS and Oxidative Response Systems in Plants Under Biotic and Abiotic Stresses: Revisiting the Crucial Role of Phosphite Triggered Plants Defense Response.

Phosphite (Phi) is a chemical analog of orthophosphate [HPO4 3-]. It is a systemic pesticide generally known to control the prevalence of oomycetes and soil-borne diseases such as Phytophthora, Pythium, and Plasmopora species. Phi can also control disease symptoms and the spread of pathogenic bacteria, fungi, and nematodes. Phi plays critical roles as a fungicide, pesticide, fertilizer, or biostimulator. Overall, Phi can alleviate the severity of the disease caused by oomycete, fungi, pathogenic bacteria, and nematodes (leave, stem, fruit, tuber, and root) in various plants (vegetables, fruits, crops, root/tuber crops, ornamental plants, and forests). Advance research in molecular, physiological, and biochemical approaches has approved the key role of Phi in enhancing crop growth, quantity, and quality of several plant species. Phi is chemically similar to orthophosphate, and inside the cells, it is likely to get involved in different features of phosphate metabolism in both plants and pathogens. In plants, a range of physiobiochemical alterations are induced by plant pathogen stress, which causes lowered photosynthesis activities, enzymatic activities, increased accumulation of reactive oxygen species (ROS), and modification in a large group of genes. To date, several attempts have been made to study plant-pathogen interactions with the intent to minimize the loss of crop productivity. Phi's emerging function as a biostimulant in plants has boost plant yield and tolerance against various stress factors. This review discusses Phi-mediated biostimulant effects against biotic and abiotic stresses.