Plant Communications最新文献

Root-knot nematodes (Meloidogyne spp.) have garnered significant attention from researchers due to their substantial damage to crops and worldwide distribution. However, controlling this nematode disease is challenging which results from limited chemical pesticides and biocontrol agents effective against them. Here, we demonstrate that pepper-rotation markedly reduces Meloidogyne incognita infection in cucumber and diminishes the presence of p-hydroxybenzoic acid in the soil, a compound known to exacerbate M. incognita infection. Pepper-rotation also structures the rhizobacterial community, leading to the colonization of two Pseudarthrobacter oxydans strains (RH60 and RH97) in the cucumber rhizosphere, facilitated by palmitic acid enrichment in pepper root exudates. Furthermore, both strains exhibit high nematocidal activity against M. incognita, and possess the ability to biosynthesize indoleacetic acid and biodegrade p-hydroxybenzoic acid. RH60 and RH97 additionally induce systemic resistance in cucumber plants and promote their growth. These data suggest that pepper root-exudate palmitic acid alleviates M. incognita infection by recruiting beneficial P. oxydans in the cucumber rhizosphere. Our analyses identify a novel chemical component in root exudates and uncover its pivotal role in crop rotation for disease attenuation, providing intriguing insights into the keystone function of root exudates in plant protection against root-knot nematode infection.

Single nucleotide polymorphisms (SNPs) are widely used as molecular markers for constructing genetic linkage maps in wheat. Compared with available SNP-based genotyping platforms, a genotyping by target sequencing (GBTS) system with capture-in-solution (liquid chip) technology has become the favored genotyping technology because it is less demanding and more cost-effective, flexible and user-friendly. In this study, a new GenoBaits®WheatSNP16K (GBW16K) GBTS array was designed based on data sets generated by the wheat 660K SNP array and re-sequencing platforms in our previous studies. The GBW16K array contained 14,868 target SNP regions that were evenly distributed across the wheat genome and 37,669 SNPs in those regions were identified in a diversity panel consisting of 239 wheat accessions from around the world. Principal component and neighbor-joining analysis using the calling SNPs were consistent with the pedigree information and geographical distribution or ecological environments of the accessions. For the GBW16K marker panel, the average genetic diversity among the 239 accessions was 0.270 which is sufficient for linkage map construction and preliminary mapping of targeted genes/QTLs. A genetic linkage map of a RIL population derived from a cross of CIMMYT wheat line Yaco"S" and Chinese landrace Mingxian169 constructed using the GBW16K array enabled identification of Yr27, Yr30 and QYr.nwafu-2BL.4 for adult plant resistance (APR) to stripe rust from Yaco"S" and Yr18 from Mingxian169. QYr.nwafu-2BL.4 was different from any previously reported gene/QTL. Three haplotypes and six candidate genes have been identified for QYr.nwafu-2BL.4 based on haplotype analysis, micro-collinearity, gene annotation, RNA-seq and SNP data. This array provides a new resource tool for wheat genetic analysis and breeding studies and for achieving durable control of wheat stripe rust.

Ash trees (Fraxinus) exhibit rich genetic diversity and wide adaptation to various ecological environments, and several species are highly salt tolerant. Dissecting the genomic basis of salt adaptation in Fraxinus is vital for its resistance breeding. Here, we present 11 high-quality chromosome-level genome assemblies for Fraxinus species, which reveal two unequal subgenome compositions and two recent whole-genome triplication events in their evolutionary history. A Fraxinus pan-genome was constructed on the basis of structural variations and revealed that presence-absence variations (PAVs) of transmembrane transport genes have likely contributed to salt adaptation in Fraxinus. Through whole-genome resequencing of an F1 population from an interspecies cross of F. velutina 'Lula 3' (salt tolerant) with F. pennsylvanica 'Lula 5' (salt sensitive), we mapped salt-tolerance PAV-based quantitative trait loci (QTLs) and pinpointed two PAV-QTLs and candidate genes associated with Fraxinus salt tolerance. Mechanistically, FvbHLH85 enhances salt tolerance by mediating reactive oxygen species and Na⁺/K⁺ homeostasis, whereas FvSWEET5 enhances salt tolerance by mediating osmotic homeostasis. Collectively, these findings provide valuable genomic resources for Fraxinus salt-resistance breeding and the research community.

Plasma membrane intrinsic proteins (PIPs), a subclass of aquaporins, play an important role in plant immunity by acting as H₂O₂ transporters. Their homeostasis is mostly maintained by C-terminal serine phosphorylation. However, the kinases that phosphorylate PIPs and manipulate their turnover are largely unknown. Here, we found that Arabidopsis thaliana PIP2;7 positively regulates plant immunity by transporting H₂O₂. Arabidopsis CALCIUM-DEPENDENT PROTEIN KINASE 28 (CPK28) directly interacts with and phosphorylates PIP2;7 at Ser273/276 to induce its degradation. During pathogen infection, CPK28 dissociates from PIP2;7 and destabilizes, leading to PIP2;7 accumulation. As a countermeasure, oomycete pathogens produce conserved kinase effectors that stably bind to and mediate the phosphorylation of PIP2;7 to induce its degradation. Our study identifies PIP2;7 as a novel substrate of CPK28 and shows that its protein stability is negatively regulated by CPK28. Such phosphorylation could be mimicked by Phytophthora kinase effectors to promote infection. Accordingly, we developed a strategy to combat oomycete infection using a phosphorylation-resistant PIP2;7^S273/276A mutant. The strategy only allows accumulation of PIP2;7^S273/276A during infection to limit potential side effects on normal plant growth.

Proper mitochondrial function is crucial to plant growth and development. Inhibition of mitochondrial translation leads to mitochondrial proteotoxic stress, which triggers a protective transcriptional response that regulates nuclear gene expression, commonly referred to as the mitochondrial unfolded protein response (UPR^mt). Although the UPR^mt has been extensively studied in yeast and mammals, very little is known about the UPR^mt in plants. Here, we show that mitochondrial translational stress inhibits plant growth and development by inducing jasmonic acid (JA) biosynthesis and signaling. The inhibitory effect of mitochondrial translational stress on plant growth was alleviated in the JA-signaling-defective mutants coi1-2, myc2, and myc234. Genetic analysis indicated that Arabidopsis mitochondrial ribosomal protein L1 (MRPL1), a key factor in the UPR^mt, regulates plant growth in a CORONATINE-INSENSITIVE 1 (COI1)-dependent manner. Moreover, under mitochondrial translational stress, MYC2 shows direct binding to G boxes in the ETHYLENE RESPONSE FACTOR 109 (ERF109) promoter. The induction of ERF109 expression enhances hydrogen peroxide production, which acts as a feedback loop to inhibit root growth. In addition, mutation of MRPL1 increases JA accumulation, reduces plant growth, and enhances biotic stress resistance. Overall, our findings reveal that JA plays an important role in mediating retrograde signaling under mitochondrial translational stress to balance plant growth and defense.

Flavonoids, the largest class of polyphenols, exhibit substantial structural and functional diversity, yet their evolutionary diversification and specialized functions remain largely unexplored. The genus Scutellaria is notable for its rich flavonoid diversity, particularly of 6/8-hydroxylated variants biosynthesized by the cytochrome P450 subfamily CYP82D. Our study analyzes metabolic differences between Scutellaria baicalensis and Scutellaria barbata, and the results suggest that CYP82Ds have acquired a broad range of catalytic functions over their evolution. By integrating analyses of metabolic networks and gene evolution across 22 Scutellaria species, we rapidly identified 261 flavonoids and delineated five clades of CYP82Ds associated with various catalytic functions. This approach revealed a unique catalytic mode for 6/8-hydroxylation of flavanone substrates and the first instance of 7-O-demethylation of flavonoid substrates catalyzed by a cytochrome P450. Ancestral sequence reconstruction and functional validation demonstrated that gradual neofunctionalization of CYP82Ds has driven the chemical diversity of flavonoids in the genus Scutellaria throughout its evolutionary history. These findings enhance our understanding of flavonoid diversity, reveal the intricate roles of CYP82Ds in Scutellaria species, and highlight the extensive catalytic versatility of cytochrome P450 members within plant taxa.