Activation of the VQ Motif-Containing Protein Gene VQ28 Compromised Nonhost Resistance of Arabidopsis thaliana to Phytophthora Pathogens

Meta-QTL analysis and identification of candidate genes for multiple-traits associated with spot blotch resistance in bread wheat

In bread wheat, a literature search gave 228 QTLs for six traits, including resistance against spot blotch and the following five other related traits: (i) stay green; (ii) flag leaf senescence; (iii) green leaf area duration; (iv) green leaf area of the main stem; and (v) black point resistance. These QTLs were used for metaQTL (MQTL) analysis. For this purpose, a consensus map with 72,788 markers was prepared; 69 of the above 228 QTLs, which were suitable for MQTL analysis, were projected on the consensus map. This exercise resulted in the identification of 16 meta-QTLs (MQTLs) located on 11 chromosomes, with the PVE ranging from 5.4% (MQTL7) to 21.8% (MQTL5), and the confidence intervals ranging from 1.5 to 20.7 cM (except five MQTLs with a range of 36.1-57.8 cM). The number of QTLs associated with individual MQTLs ranged from a maximum of 17 in MQTL3 to 8 each in MQTL5 and MQTL8 and 5 each in MQTL7 and MQTL14. The 16 MQTLs, included 12 multi-trait MQTLs; one of the MQTL also overlapped a genomic region carrying the major spot blotch resistance gene Sb1. Of the total 16 MQTLs, 12 MQTLs were also validated through marker-trait associations that were available from earlier genome-wide association studies. The genomic regions associated with MQTLs were also used for the identification of candidate genes (CGs) and led to the identification of 516 CGs encoding 508 proteins; 411 of these proteins are known to be associated with resistance against several biotic stresses. In silico expression analysis of CGs using transcriptome data allowed the identification of 71 differentially expressed CGs, which were examined for further possible studies. The findings of the present study should facilitate fine-mapping and cloning of genes, enabling Marker Assisted Selection.

The role and pathway of VQ family in plant growth, immunity, and stress response

MAIN CONCLUSION

This review provides a detailed description of the function and mechanism of VQ family gene, which is helpful for further research and application of VQ gene resources to improve crops. Valine-glutamine (VQ) motif-containing proteins are a large class of transcriptional regulatory cofactors. VQ proteins have their own unique molecular characteristics. Amino acids are highly conserved only in the VQ domain, while other positions vary greatly. Most VQ genes do not contain introns and the length of their proteins is less than 300 amino acids. A majority of VQ proteins are predicted to be localized in the nucleus. The promoter of many VQ genes contains stress or growth related elements. Segment duplication and tandem duplication are the main amplification mechanisms of the VQ gene family in angiosperms and gymnosperms, respectively. Purification selection plays a crucial role in the evolution of many VQ genes. By interacting with WRKY, MAPK, and other proteins, VQ proteins participate in the multiple signaling pathways to regulate plant growth and development, as well as defense responses to biotic and abiotic stresses. Although there have been some reports on the VQ gene family in plants, most of them only identify family members, with little functional verification, and there is also a lack of complete, detailed, and up-to-date review of research progress. Here, we comprehensively summarized the research progress of VQ genes that have been published so far, mainly including their molecular characteristics, biological functions, importance of VQ motif, and working mechanisms. Finally, the regulatory network and model of VQ genes were drawn, a precise molecular breeding strategy based on VQ genes was proposed, and the current problems and future prospects were pointed out, providing a powerful reference for further research and utilization of VQ genes in plant improvement.

Large-Scale Identification and Characterization Analysis of VQ Family Genes in Plants, Especially Gymnosperms

VQ motif-containing (VQ) proteins are a class of transcription regulatory cofactors widely present in plants, playing crucial roles in growth and development, stress response, and defense. Although there have been some reports on the member identification and functional research of VQ genes in some plants, there is still a lack of large-scale identification and clear graphical presentation of their basic characterization information to help us to better understand this family. Especially in gymnosperms, the VQ family genes and their evolutionary relationships have not yet been reported. In this study, we systematically identified 2469 VQ genes from 56 plant species, including bryophytes, gymnosperms, and angiosperms, and analyzed their molecular and evolutionary features. We found that amino acids are only highly conserved in the VQ domain, while other positions are relatively variable; most VQ genes encode relatively small proteins and do not have introns. The GC content in Poaceae plants is the highest (up to 70%); these VQ proteins can be divided into nine subgroups. In particular, we analyzed the molecular characteristics, chromosome distribution, duplication events, and expression levels of VQ genes in three gymnosperms: Ginkgo biloba, Taxus chinensis, and Pinus tabuliformis. In gymnosperms, VQ genes are classified into 11 groups, with highly similar motifs in each group; most VQ proteins have less than 300 amino acids and are predicted to be located in nucleus. Tandem duplication is an important driving force for the expansion of the VQ gene family, and the evolutionary processes of most VQ genes and duplication events are relatively independent; some candidate VQ genes are preliminarily screened, and they are likely to be involved in plant growth and stress and defense responses. These results provide detailed information and powerful references for further understanding and utilizing the VQ family genes in various plants.

Genome-Wide Identification and Characterization of the VQ Motif-Containing Gene Family Based on Their Evolution and Expression Analysis under Abiotic Stress and Hormone Treatments in Foxtail Millet (Setaria italica L.)

Valine-glutamine (VQ) motif-containing proteins are transcriptional regulatory cofactors that play critical roles in plant growth and response to biotic and abiotic stresses. However, information on the VQ gene family in foxtail millet (Setaria italica L.) is currently limited. In this study, a total of 32 SiVQ genes were identified in foxtail millet and classified into seven groups (I-VII), based on the constructed phylogenetic relationships; the protein-conserved motif showed high similarity within each group. Gene structure analysis showed that most SiVQs had no introns. Whole-genome duplication analysis revealed that segmental duplications contributed to the expansion of the SiVQ gene family. The cis-element analysis demonstrated that growth and development, stress response, and hormone-response-related cis-elements were all widely distributed in the promoters of the SiVQs. Gene expression analysis demonstrated that the expression of most SiVQ genes was induced by abiotic stress and phytohormone treatments, and seven SiVQ genes showed significant upregulation under both abiotic stress and phytohormone treatments. A potential interaction network between SiVQs and SiWRKYs was predicted. This research provides a basis to further investigate the molecular function of VQs in plant growth and abiotic stress responses.