Genome-Wide Analysis of the Five Phosphate Transporter Families in Camelina sativa and Their Expressions in Response to Low-P.

Dhondup Lhamo,Sheng Luan,Qiaolin Shao,Renjie Tang

doi:10.3390/ijms21218365

Abstract

Phosphate transporters (PHTs) play pivotal roles in phosphate (Pi) acquisition from the soil and distribution throughout a plant. However, there is no comprehensive genomic analysis of the PHT families in Camelina sativa, an emerging oilseed crop. In this study, we identified 73 CsPHT members belonging to the five major PHT families. A whole-genome triplication event was the major driving force for CsPHT expansion, with three homoeologs for each Arabidopsis ortholog. In addition, tandem gene duplications on chromosome 11, 18 and 20 further enlarged the CsPHT1 family beyond the ploidy norm. Phylogenetic analysis showed clustering of the CsPHT1 and CsPHT4 family members into four distinct groups, while CsPHT3s and CsPHT5s were clustered into two distinct groups. Promoter analysis revealed widespread cis-elements for low-P response (P1BS) specifically in CsPHT1s, consistent with their function in Pi acquisition and translocation. In silico RNA-seq analysis revealed more ubiquitous expression of several CsPHT1 genes in various tissues, whereas CsPHT2s and CsPHT4s displayed preferential expression in leaves. While several CsPHT3s were expressed in germinating seeds, most CsPHT5s were expressed in floral and seed organs. Suneson, a popular Camelina variety, displayed better tolerance to low-P than another variety, CS-CROO, which could be attributed to the higher expression of several CsPHT1/3/4/5 family genes in shoots and roots. This study represents the first effort in characterizing CsPHT transporters in Camelina, a promising polyploid oilseed crop that is highly tolerant to abiotic stress and low-nutrient status, and may populate marginal soils for biofuel production.

Highlights

Phosphorus (P) is an essential macronutrient in all organisms, which provides a backbone to nucleic acids, a polarity to cell membranes, and participates in energy transfer and signal transduction processes [1,2]
We identified 73 CsPHT genes in Camelina by blasting the coding sequences of known Arabidopsis AtPHTs against the Camelina genome
Tandem gene duplication events were the major driving force for the expansion of these CsPHT1 genes on chromosome 11, 18 and 20. These tandem duplicated genes largely correspond to AtPHT1;1/1;2/1;3 orthologs, which are functionally redundant genes that function as key players in Pi uptake [7,65]

Summary

Introduction

Phosphorus (P) is an essential macronutrient in all organisms, which provides a backbone to nucleic acids, a polarity to cell membranes, and participates in energy transfer and signal transduction processes [1,2]. To support sustainable agriculture and the environment, a widely accepted strategy is to minimize fertilizer use by breeding crops with higher P use efficiency (PUE) To achieve this goal, it is necessary to understand the molecular mechanism underlying Pi uptake from soil by roots, translocation from roots to the above-ground organs, storage into and remobilization from various subcellular compartments, and recycling from source (senescing leaves) to sink (young leaves, reproductive tissues and roots). It is necessary to understand the molecular mechanism underlying Pi uptake from soil by roots, translocation from roots to the above-ground organs, storage into and remobilization from various subcellular compartments, and recycling from source (senescing leaves) to sink (young leaves, reproductive tissues and roots) All these processes require a specific set of transport proteins located in the plasma membrane of various plant cells and membranes of their subcellular compartments

Methods

Discussion

Conclusion