StMADS11 Subfamily Gene PfMADS16 From Polypogon fugax Regulates Early Flowering and Seed Development.

Feng-Yan Zhou,Chuan-Chun Yao,Yong Zhang,Yun-Jing Han,Qin Yu

doi:10.3389/fpls.2020.00525

Abstract

The evolution of herbicide resistance in weedy plants leads to various adaptation traits including flowering time and seed germination. In our previous studies, we found an association of the early flowering phenotype with the ACCase inhibitor herbicide resistance genotype in a population of Polypogon fugax. MADS-box transcription factors are known to play pivotal roles in regulating plant flowering time. In this study, a SHORT VEGETATIVE PHASE (SVP)-like gene, belonging to the StMADS11 subfamily in the MADS-box family, was cloned from the early flowering P. fugax population (referred to as PfMADS16) and resistant to the herbicide clodinafop- propargyl. Overexpression of the SVP-like gene PfMADS16 in Arabidopsis thaliana resulted in early flowering and seed abortion. This is consistent with the phenotypic characters of resistant P. fugax plants, but contrary to the conventional role of SVP-like genes that usually suppress flowering. In addition, down regulation of the seed formation gene AtKTN1 in flowers of PfMADS16 transgenic Arabidopsis plants indicates that PfMADS16 may be indirectly associated with seed viability. Furthermore, one protein (PfMADS2) from the APETALA1 (AP1) subfamily interacting with PfMADS16 in P. fugax was identified with relevance to flowering time regulation. These results suggest that the PfMADS16 gene is an early flowering regulation gene associated with seed formation and viability in resistant P. fugax population. Our study provides potential application of PfMADS16 for integrated weed management (such as genetic-based weed control strategies) aiming to reduce the soil weed seedbank.

Highlights

Herbicide weed control is the dominant and most intensive selective force imposed in modern agriculture, resulting in widespread evolution of herbicide resistance in many weed species worldwide (Heap, 2020)
Phylogenetic analysis of PfMADS16 and SHORT VEGETATIVE PHASE (SVP)/StMADS11-like genes from plant species showed that PfMADS16 clustered closely to the SVP-like genes of F. pratensis MADS16 (ADW23676.1) and L. perenne MADS16 (AAZ17551.1), and rice OsMADS22, OsMADS55 and OsMADS47 (Sentoku et al, 2005), Dimocarpus longan DlSVP, Arabidopsis SVP, Aquilegia formosa AfSVP.2, and Magnolia praecocissima MpMADS1
This group is distinct from Arabidopsis AGAMOUS-Like 24 (AGL24) and SUPPRESSOR OF CONSTANS OVEREXPRESSION1 (SOC1) proteins (Supplementary Figure S2A)

Summary

Introduction

Herbicide weed control is the dominant and most intensive selective force imposed in modern agriculture, resulting in widespread evolution of herbicide resistance in many weed species worldwide (Heap, 2020). Herbicide-resistant plants exhibit changes in leaf canopy shape (Bravo et al, 2017), plant size and growth rate (VanEtten et al, 2016; Bravo et al, 2017), flowering time and seed germination rate (Wang et al, 2010) compared to susceptible counterparts. A Hordeum glaucum biotype resistant to ACCase-inhibiting herbicides flowered earlier than the susceptible biotype in the field and exhibited reduced seed production in competition with Lens culinaris (Shergill et al, 2016). A glyphosate-resistant population of Conyza bonariensis flowered 28 days earlier and had higher seed germination and production than the susceptible population (Kaspary et al, 2017)

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Conclusion