Genome-wide and comparative phylogenetic analysis of senescence-associated NAC transcription factors in sunflower (Helianthus annuus)

Sofia A Bengoa Luoni,Alberto Cenci,Laura M Radonic,Julia V Sabio Y García,Paula Fernandez,Salvador Nicosia,Cecilia Vazquez Rovere,Nicolas B Langlade,Denis Vile,Sebastian Moschen

doi:10.1186/s12864-021-08199-5

Abstract

BackgroundLeaf senescence delay impacts positively in grain yield by maintaining the photosynthetic area during the reproductive stage and during grain filling. Therefore a comprehensive understanding of the gene families associated with leaf senescence is essential. NAC transcription factors (TF) form a large plant-specific gene family involved in regulating development, senescence, and responses to biotic and abiotic stresses. The main goal of this work was to identify sunflower NAC TF (HaNAC) and their association with senescence, studying their orthologous to understand possible functional relationships between genes of different species.ResultsTo clarify the orthologous relationships, we used an in-depth comparative study of four divergent taxa, in dicots and monocots, with completely sequenced genomes (Arabidopsis thaliana, Vitis vinifera, Musa acuminata and Oryza sativa). These orthologous groups provide a curated resource for large scale protein sequence annotation of NAC TF. From the 151 HaNAC genes detected in the latest version of the sunflower genome, 50 genes were associated with senescence traits. These genes showed significant differential expression in two contrasting lines according to an RNAseq assay. An assessment of overexpressing the Arabidopsis line for HaNAC001 (a gene of the same orthologous group of Arabidopsis thaliana ORE1) revealed that this line displayed a significantly higher number of senescent leaves and a pronounced change in development rate.ConclusionsThis finding suggests HaNAC001 as an interesting candidate to explore the molecular regulation of senescence in sunflower.

Highlights

Leaf senescence delay impacts positively in grain yield by maintaining the photosynthetic area during the reproductive stage and during grain filling
Orthologous groups of NAC genes in H. annuus genome The genomic analysis showed that the InterPro protein domain IPR003441 was present in 164 out of 71,289 automatically predicted proteins in the H. annuus genome V2
A BLASTp analysis on whole NAC sequences set of four species representative of monocotyledonous (M. acuminata, O. sativa) and dicotyledonous species (A. thaliana, V. vinifera) assigned the 151 potentially functional NAC genes into 38 of 40 orthologous groups (OGs) defined by Cenci et al [28] (Table 1)

Summary

Introduction

Leaf senescence delay impacts positively in grain yield by maintaining the photosynthetic area during the reproductive stage and during grain filling. The main goal of this work was to identify sunflower NAC TF (HaNAC) and their association with senescence, studying their orthologous to understand possible functional relationships between genes of different species. NAC are plant specific TFs originally characterized in a Petunia NAM mutant [20] and subsequently in Arabidopsis CUC [21] and ATAF mutants. Among these proteins, ORE1 is one of the most studied NAC TFs in Arabidopsis leaf senescence. ORE1 is one of the most studied NAC TFs in Arabidopsis leaf senescence This TF is expressed during ethylene-induced senescence under the control of ETHYLENE INSENSITIVE 2, EIN2 [22]. ORE1 induces distinctive senescence features, including the degradation of nucleic acid, proteins and nitrogen recycling as well as the promotion of sugar transport [24, 25]

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