Genome-wide Identification and Characterization of FCS-Like Zinc Finger (FLZ) Family Genes in Maize (Zea mays) and Functional Analysis of ZmFLZ25 in Plant Abscisic Acid Response.

Shunquan Chen,Wei Yan,Chuanliang Liu,Xibao Li,Caiji Gao,Xiaoyan Tang,Chao Yang

doi:10.3390/ijms22073529

Shunquan Chen, Wei Yan + Show 5 more

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https://doi.org/10.3390/ijms22073529

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Abstract

FCS-like zinc finger family proteins (FLZs), a class of plant-specific scaffold of SnRK1 complex, are involved in the regulation of various aspects of plant growth and stress responses. Most information of FLZ family genes was obtained from the studies in Arabidopsis thaliana, whereas little is known about the potential functions of FLZs in crop plants. In this study, 37 maize FLZ (ZmFLZ) genes were identified to be asymmetrically distributed on 10 chromosomes and can be divided into three subfamilies. Protein interaction and subcellular localization assays demonstrated that eight typical ZmFLZs interacted and partially co-localized with ZmKIN10, the catalytic α-subunit of the SnRK1 complex in maize leaf mesophyll cells. Expression profile analysis revealed that several ZmFLZs were differentially expressed across various tissues and actively responded to diverse abiotic stresses. In addition, ectopic overexpression of ZmFLZ25 in Arabidopsis conferred hypersensitivity to exogenous abscisic acid (ABA) and triggered higher expression of ABA-induced genes, pointing to the positive regulatory role of ZmFLZ25 in plant ABA signaling, a scenario further evidenced by the interactions between ZmFLZ25 and ABA receptors. In summary, these data provide the most comprehensive information on FLZ family genes in maize, and shed light on the biological function of ZmFLZ25 in plant ABA signaling.

Highlights

The first FLZ-domain containing protein MEDIATOR OF ABA-REGULATED DORMANCY 1 (MARD1) was identified from senescence related enhancer-trapping and found to be implicated in abscisic acid (ABA)-mediated seed dormancy in Arabidopsis [1,2]
37 independent FLZ proteins (ZmFLZs) were identified in maize genome (B73) (Figure 1A and Table S1). These 37 putative ZmFLZs were submitted to NCBI Batch-CD and Pfam to confirm the existence of FLZ domain (Figure 1B), and their corresponding coding genes were orderly named ZmFLZ1 to ZmFLZ37 in accordance with their locations on the chromosomes of maize (Table S1)
These 37 ZmFLZ genes are unevenly distributed on the 10 chromosomes, and the highest numbers of them are found on chromosomes 2, 4 and

Summary

Introduction

The first FLZ-domain containing protein MEDIATOR OF ABA-REGULATED DORMANCY 1 (MARD1) was identified from senescence related enhancer-trapping and found to be implicated in abscisic acid (ABA)-mediated seed dormancy in Arabidopsis [1,2]. MARD1 possesses a novel zinc finger domain that shares high signature motif similarity with MYM-type zinc finger containing FCS sequence motif [2] This domain was found to be exclusively existed in plants and designated as the FCS-Like Zinc finger (FLZ) domain or Domains of Unknown Function 581 (DUF581), which consists of around 70 amino acid residues harboring an identical CX2CX17-19FCSX2C motif [3,4]. AtFLZ genes were found to be highly responsive to plant hormone and nutritional cues, as well as various abiotic stresses, such as ABA, nitrogen starvation and high concentration of salt [4] These studies highlight the potential roles of FLZ family genes during plant growth and stress response. Both AtFLZ6 and AtFLZ10 knock-down Arabidopsis mutants display higher sensitivity to ABA-repressed root elongation and lower tolerance to osmotic stress [7,8], albeit the underlying molecular mechanisms remain elusive

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