Genome-Wide Analysis of Purple Acid Phosphatase Genes in Brassica rapa and Their Association with Pollen Development and Phosphorus Deprivation Stress

Yongfang Cai,Jing Gao,Xiaoshuang Yang,Chun Li,Baixue Jiang,Xiangshu Dong,Wenyu Han,Jiao Qi,Kehui Miao,Yang Wang

doi:10.3390/horticulturae7100363

Abstract

PAPs (purple acid phosphatases) belong to the metallo-phosphoesterase superfamily and play important roles in developmental processes, phosphorus foraging, and recycling. However, the specific functions of BrPAPs in Brassica rapa are poorly understood. In this study, 39 BrPAPs were identified and divided into three major clades and nine subgroups. In 8 of the 39 BrPAPs, some invariant amino acid residues were lost or shifted. Based on an expression profiling analysis, BrPAP11, 14, 20, 24, 29, and 34 were specifically expressed in fertile floral buds, indicating their critical roles during pollen development. A total of 21 BrPAPs responded to Pi deprivation in either shoots or roots. Of these, BrPAP4, 5, 19, and 21 were upregulated in roots under Pi depravation conditions, while BrPAP12 was upregulated in the roots in normal conditions. BrPAP28 was upregulated in shoots under Pi depravation conditions, indicating its function shifted compared with its Arabidopsis homolog, AtPAP26. The present work contributes to further investigation of BrPAPs as candidate genes for genetic improvement studies of low phosphorus tolerance as well as for creating male sterile lines based on gene editing methods in Brassica rapa.

Highlights

Purple acid phosphatases (PAPs) belong to the metallo-phosphoesterase superfamily and are a type of acid phosphatase (APase) comprised of a binuclear metal center bindingFe (III)-M (II) complex at the active site [1,2]
The results from this study provide a basis for further understanding of the functions of BrPAPs during pollen development and B. rapa responses to Pi deprivation
After BLASTP search and conserved motif determination, 39 PAP genes were identified from the B. rapa genome and designated as BrPAP1 to BrPAP39 according to their positions on chromosomes (Figure 1)

Summary

Introduction

Due to the existence of a tyrosine residue ligated to a ferric iron, this group of acid phosphatases has a purple color [3]. They have been isolated from most eukaryotic organisms and some bacteria [3,4]. Improvement of APase activity is an important avenue for improving the efficiency of phosphorus utilization of plants in a low Pi (inorganic phosphate) environment. This enables plants to utilize extracellular and intracellular organic phosphorus (Po) [5,6,7]

Methods

Results

Discussion

Conclusion