Phosphate is a vital macronutrient for plant growth, and its availability in soil is critical for agricultural sustainability and productivity. A substantial amount of cellular phosphate is used to synthesize phospholipids for cell membranes. Here, we identify a key enzyme, nonspecific phospholipase C4 (NPC4) that is involved in phosphosphingolipid hydrolysis and remodeling in Arabidopsis during phosphate starvation. The level of glycosylinositolphosphorylceramide (GIPC), the most abundant sphingolipid in Arabidopsis thaliana, decreased upon phosphate starvation. NPC4 was highly induced by phosphate deficiency, and NPC4 knockouts in Arabidopsis decreased the loss of GIPC and impeded root growth during phosphate starvation. Enzymatic analysis showed that NPC4 hydrolyzed GIPC and displayed a higher activity toward GIPC as a substrate than toward the common glycerophospholipid phosphatidylcholine. NPC4 was associated with the plasma membrane lipid rafts in which GIPC is highly enriched. These results indicate that NPC4 uses GIPC as a substrate in planta and the NPC4-mediated sphingolipid remodeling plays a positive role in root growth in Arabidopsis response to phosphate deficiency.
24Cotton bacterial blight (CBB), an important disease of (Gossypium hirsutum)
Cotton bacterial leaf blight (CBB), caused by Xanthomonas citri subsp. malvacearum (Xcm) has been periodically a damaging disease in the U.S.A. Identi cation and deployment of genetic resistance in the cotton cultivars is the most economical and e cient means of reducing the crop losses due to CBB. In the current study, a combined genome-wide association study (GWAS) and linkage-mapping approach was used to map the CBB resistance gene in Upland cotton. An elite diversity panel of 380 accessions, genotyped with the Cotton 63K single nucleotide polymorphism (SNP) array and phenotyped with race-18 of CBB was used in the GWAS. The GWAS localized the CBB resistance to a 2.01 Mb region in the long arm of chromosome D02. Mapping of this CBB resistance was further resolved using linkage mapping in an F 6 recombinant inbred line (RIL) population derived from Acala Maxxa × Arkot 8102. The CBB resistance in Arkot 8102 showed monogenic inheritance. The CBB resistance locus (BB-13) was mapped within the 0.95 cM interval near the telomeric region in the long arm of chromosome D02. Flanking SNP markers, i25755Gh (p = 19.29) and i46775Gh (p = 19.29) of the BB-13 locus from the linkage analysis showed the highest signi cant marker-trait associations (MTAs) in the GWAS study. Using these SNPs, we targeted the BB-13 locus to a 371 Kb genomic region on chromosome D02. Candidate gene analysis identi ed thirty putative gene sequences in the targeted region. Nine of the thirty putative genes were involved in disease resistance in plants. Key MessageIdenti cation and genomic characterization of major resistance locus against cotton bacterial blight (CBB) using GWAS and linkage mapping to enable genomics-based development of durable CBB resistance and gene discovery in cotton.
Cotton bacterial blight (CBB), an important disease of (Gossypium hirsutum) in the early 20th century, had been controlled by resistant germplasm for over half a century. Recently, CBB re-emerged as an agronomic problem in the United States. Here, we report analysis of cotton variety planting statistics that indicate a steady increase in the percentage of susceptible cotton varieties grown each year since 2009. Phylogenetic analysis revealed that strains from the current outbreak cluster with race 18 Xanthomonas citri pv. malvacearum (Xcm) strains. Illumina based draft genomes were generated for thirteen Xcm isolates and analyzed along with 4 previously published Xcm genomes. These genomes encode 24 conserved and nine variable type three effectors. Strains in the race 18 clade contain 3 to 5 more effectors than other Xcm strains. SMRT sequencing of two geographically and temporally diverse strains of Xcm yielded circular chromosomes and accompanying plasmids. These genomes encode eight and thirteen distinct transcription activator-like effector genes. RNA-sequencing revealed 52 genes induced within two cotton cultivars by both tested Xcm strains. This gene list includes a homeologous pair of genes, with homology to the known susceptibility gene, MLO. In contrast, the two strains of Xcm induce different clade III SWEET sugar transporters. Subsequent genome wide analysis revealed patterns in the overall expression of homeologous gene pairs in cotton after inoculation by Xcm. These data reveal important insights into the Xcm-G. hirsutum disease complex and strategies for future development of resistant cultivars.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.