Transcriptome analysis provides new insights into plants responses under phosphate starvation in association with chilling stress

Xiaoning Gao,Jun Kang,Ayesha T Tahir,Fatemeh Rasouli,Ali Kiani Pouya,Jinsong Dong

doi:10.1186/s12870-021-03381-z

Abstract

BackgroundChilling temperature reduces the rate of photosynthesis in plants, which is more pronounced in association with phosphate (Pi) starvation. Previous studies showed that Pi resupply improves recovery of the rate of photosynthesis in plants much better under combination of dual stresses than in non-chilled samples. However, the underlying mechanism remains poorly understood.Results In this study, RNA-seq analysis showed the expression level of 41 photosynthetic genes in plant roots increased under phosphate starvation associated with 4 °C (-P 4 °C) compared to -P 23 °C. Moreover, iron uptake increased significantly in the stem cell niche (SCN) of wild type (WT) roots in -P 4 °C. In contrast, lower iron concentrations were found in SCN of aluminum activated malate transporter 1 (almt1) and its transcription factor, sensitive to protein rhizotoxicity 1 (stop1) mutants under -P 4 °C. The Fe content examined by ICP-MS analysis in -P 4 °C treated almt1 was 98.5 ng/µg, which was only 17% of that of seedlings grown under -P 23 °C. Average plastid number in almt1 root cells under -P 4 °C was less than -P 23 °C. Furthermore, stop1 and almt1 single mutants both exhibited increased primary root elongation than WT under combined stresses. In addition, dark treatment blocked the root elongation phenotype of stop1 and almt1.ConclusionsInduction of photosynthetic gene expression and increased iron accumulation in roots is required for plant adjustment to chilling in association with phosphate starvation.

Highlights

Chilling temperature reduces the rate of photosynthesis in plants, which is more pronounced in association with phosphate (Pi) starvation
RNA‐seq analyses of the root transcriptome under chilling stress and Pi starvation To elucidate the molecular mechanisms under combined action of cold stress and Pi starvation (-P) in plant roots, a comparative RNA-seq analysis of root transcriptome was performed. cDNA libraries were constructed from the roots of 7-day-old wild type (WT) seedlings using the total RNA, which were divided into four groups according to the growth condition to which they were subjected: +P medium, -P medium, °C, or transferred to 4 °C for h
In -P 4 °C treated stop1, Fe content was 373.5 ng/μg (Fig. 3). These results suggested that the enhanced Fe accumulation in plant root tips under -P 4 °C might be caused by ALMT1 and STOP1

Summary

Introduction

Chilling temperature reduces the rate of photosynthesis in plants, which is more pronounced in association with phosphate (Pi) starvation. Previous studies showed that Pi resupply improves recovery of the rate of photosynthesis in plants much better under combination of dual stresses than in non-chilled samples. Plants have to evolve strategies such as efficient use of inorganic phosphate (Pi), the major form of P available from soil, to overcome the low Pi availability in many agricultural systems [1]. The efficiency of photosynthetic electron transport in plants is reduced by low temperatures and in combination with high light treatment could even lead to photoinhibition by implication of photosystem I (PSI) instead of PSII [7, 8]. Alterations in system functioning can lead to change in homeostasis of Fe as well as oxidation-reduction reactions controlled by iron-sulfur (Fe-S) centers (Fe-Sx, FeSA, and FeSB) in the PS I system [9]

Methods

Results

Discussion

Conclusion