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Background: The interaction among plants and their pollinators has been a major factor which enriched floral traits known as pollination syndromes and promoted the diversification of flowering plants. One of the bee-pollination syndromes in Faboideae with keel blossoms is the formation of a landing platform by wing and keel petals. However, the molecular mechanisms of elaborating a keel blossom remain unclear. Results: By performing large scale mutagenesis, we isolated and characterized a mutant in Vigna radiata, love on wings (low), which shows developmental defects in petal asymmetry and vasculature, leading to a failure in landing platform formation. We cloned the locus through map-based cloning together with RNA-sequencing (RNA-seq) analysis. We found that LOW encoded a nucleus-localized Dof-like protein and was expressed in the flower provascular and vascular tissues. A single copy of LOW was detected in legumes, in contrast with other taxa where there seems to be at least 2 copies. Thirty one Dof proteins have been identified from the V. radiata's genome, which can be further divided into four Major Cluster of Orthologous Groups (MCOGs). We also showed that ectopic expression of LOW in Arabidopsis driven by its native promoter caused changes in petal vasculature pattern. Conclusions: To summarize, our study isolated a legume Dof-like factor LOW from V. radiata, which affects vasculature development in this species and this change can, in turn, impact petal development and overall morphology of keel blossom. [ABSTRACT FROM AUTHOR]

Summary: Brown planthopper (BPH, Nilaparvata lugens), a highly destructive insect pest, poses a serious threat to rice (Oryza sativa) production worldwide. Jasmonates are key phytohormones that regulate plant defences against BPH; however, the molecular link between jasmonates and BPH responses in rice remains largely unknown. Here, we discovered a Poaceae‐specific metabolite, mixed‐linkage β‐1,3;1,4‐d‐glucan (MLG), which contributes to jasmonate‐mediated BPH resistance. MLG levels in rice significantly increased upon BPH attack. Overexpressing OsCslF6, which encodes a glucan synthase that catalyses MLG biosynthesis, significantly enhanced BPH resistance and cell wall thickness in vascular bundles, whereas knockout of OsCslF6 reduced BPH resistance and vascular wall thickness. OsMYC2, a master transcription factor of jasmonate signalling, directly controlled the upregulation of OsCslF6 in response to BPH feeding. The AT‐rich domain of the OsCslF6 promoter varies in rice varieties from different locations and natural variants in this domain were associated with BPH resistance. MLG‐derived oligosaccharides bound to the plasma membrane‐anchored LECTIN RECEPTOR KINASE1 OsLecRK1 and modulated its activity. Thus, our findings suggest that the OsMYC2‐OsCslF6 module regulates pest resistance by modulating MLG production to enhance vascular wall thickness and OsLecRK1‐mediated defence signalling during rice‐BPH interactions. [ABSTRACT FROM AUTHOR]

The diverse pigmentation patterns of flower corollas probably result from pollinator-mediated selection. Previous studies demonstrated that R2R3- MYB factors may have been recruited in the regulation of corolla pigmentation. However, how R2R3-MYBs became so diverse in their regulation of different pigmentation patterns remains unclear., Here, we studied a Lamiales species, Torenia fournieri, which has elaborate zygomorphic flowers with dorsal-ventral asymmetries in corolla pigmentation. We found recent gene duplication events in CYCLOIDEA-like ( CYC-like) and RADIALIS-like ( RAD-like) genes, and functionally analyzed three dorsal-specific expression factors: Tf CYC1, Tf CYC2, and Tf RAD1., We found that the CYC- RAD module coordinates petal shape and corolla pigmentation, as ectopic expression of Tf CYC2 or Tf RAD1 disrupted the asymmetric corolla pigmentation pattern and produced strongly dorsalized flowers. Dorsal petal identity was lost when Tf CYC2 was down-regulated or when Tf RAD1 was knocked out. In T. fournieri, the diversified CYC and RAD genes have evolved regulatory loops, and Tf CYC2 binds directly to the regulatory regions of an R2R3- MYB factor gene, Tf MYB1, which might lead to its asymmetric expression and ultimately establish the asymmetric pigmentation pattern., These findings support the existence of a regulatory module that integrates dorsal-ventral patterning and asymmetric corolla pigmentation in T. fournieri. [ABSTRACT FROM AUTHOR]

Mungbean (Vigna radiata L.) is a fast-growing warm-season legume crop widely distributed in Asia. A large amount of self-shading of mungbean plants could reduce its seed yield. Thus, modification of the leaflet type could affect the leaf canopy and improve yield. In this study, a classical locus, lobed leaflet margins (lma) in mungbean, was investigated, which was controlled by a semi-dominant allele. In order to map the lma, the whole genomes of AL127 carrying lma and another accession Sulu with oval leaflets were re-sequenced; 236,998 single nucleotide polymorphisms and 8896 insertion/deletions (InDels) were identified between the two accessions. Using the validated InDels and SNP markers, lma was mapped to a syntenic region about 376 kb on chromosome 3 in mungbean and on chromosome 1 in common bean, respectively. Our results provided a framework for map-based gene cloning in mungbean. Cloning the lma should shed light on the underlying molecular mechanism controlling leaf shape in legumes and further provide the molecular basis for genetic improvement on legume crops. [ABSTRACT FROM AUTHOR]

An orchid flower exhibits a zygomorphic corolla with a well-differentiated labellum. In Cymbidium sinense, many varieties with peloric or pseudopeloric flowers have been bred during centuries of domestication. However, little is known about the molecular basis controlling orchid floral zygomorphy and the origin of these varieties. Here, we studied the floral morphogenesis of C. sinense and transcriptome-wide enriched differentially expressed genes among different varieties. The floral zygomorphy of C. sinense is established in the early developmental process. Out of 27 MIKCC-MADS factors, we found two homeotic MADS genes whose expression was down-regulated in peloric varieties but up-regulated in pseudopeloric varieties. CsAP3-2 expressed in the inner floral organs co-operates with a labellum-specific factor CsAGL6-2, asymmetrically promoting the differentiation of inner tepals. Interestingly, we detected exon deletions on CsAP3-2 in peloric varieties, indicating that loss of B-function results in the origin of peloria. Additional petaloid structures developed when we ectopically expressed these genes in Arabidopsis, suggesting their roles in floral morphogenesis. These findings indicate that the interplay among MADS factors would be crucial for orchid floral zygomorphy, and mutations in these factors may have maintained during artificial selection. [ABSTRACT FROM AUTHOR]

Membrane Attack Complex and Perforin (MACPF) proteins play crucial roles in plant development and plant responses to environmental stresses. To date, only four MACPF genes have been identified in Arabidopsis thaliana, and the functions of the MACPF gene family members in other plants, especially in important crop plants, such as the Poaceae family, remain largely unknown. In this study, we identified and analyzed 42 MACPF genes from six completely sequenced and well annotated species representing the major Poaceae clades. A phylogenetic analysis of MACPF genes resolved four groups, characterized by shared motif organizations and gene structures within each group. MACPF genes were unevenly distributed along the Poaceae chromosomes. Moreover, segmental duplications and dispersed duplication events may have played significant roles during MACPF gene family expansion and functional diversification in the Poaceae. In addition, phylogenomic synteny analysis revealed a high degree of conservation among the Poaceae MACPF genes. In particular, Group I, II, and III MACPF genes were exposed to strong purifying selection with different evolutionary rates. Temporal and spatial expression analyses suggested that Group III MACPF genes were highly expressed relative to the other groups. In addition, most MACPF genes were highly expressed in vegetative tissues and up-regulated by several biotic and abiotic stresses. Taken together, these findings provide valuable information for further functional characterization and phenotypic validation of the Poaceae MACPF gene family. [ABSTRACT FROM AUTHOR]