Divergent Molecular and Physiological Response of Two Maize Breeding Lines Under Phosphate Deficiency

Yanling Sun,Hongxia Zheng

doi:10.1007/s11105-021-01310-w

Yanling Sun, Hongxia Zheng

Open Access

https://doi.org/10.1007/s11105-021-01310-w

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Abstract

Inorganic phosphate (Pi) deficiency is a main limiting factor on crops growth and to select low-Pi tolerant breeding lines is very significant for crop breeding. Here, two contrasting maize (Zea mays L.) breeding lines showed different physiological response to Pi deficiency. The low-Pi tolerant QXN233 maintained normal growth, including high fresh weight, green leaves, strong shoots, and numerous roots relative to that of the sensitive MH05-4, mainly due to QXN233’ high Pi content in shoots under Pi deficiency. Importantly, some Pi-responsive genes were detected, and among them, Pi transporters ZmPHT1;1 and ZmPHT1;9 as well as phytase gene Zmphytase 2 were expressed increasingly in QXN233 compared to MH05-4 under Pi deprivation or Pi resupply. Moreover, QXN233 had higher proline content, soluble sugar content, and SOD activity than MH05-4, related with its tolerance. Taken together, this study enriches the understanding of the mechanism of maize responding to Pi deficiency.

Highlights

Phosphorus (P) is an essential plant macronutrient, involved in the protein and nucleic acid biosynthesis, and energy metabolism, photosynthesis, respiration, the regulation of enzymes, and signal transduction cascades (Yang and Finnegan 2010)
The results showed that QXN233 and MH05-4 both had weakly growth under Pi deficiency compared to normal conditions (Table 3)
The results showed that proline contents were both increased in two tested breeding lines under Pi deficiency, and QXN233 has higher proline content than that of MH05-4 (Fig. 3A); the same response of soluble sugar emerged between QXN233 and MH05-4 (Fig. 3B)

Summary

Introduction

Phosphorus (P) is an essential plant macronutrient, involved in the protein and nucleic acid biosynthesis, and energy metabolism, photosynthesis, respiration, the regulation of enzymes, and signal transduction cascades (Yang and Finnegan 2010). A MYB-like transcription factor phosphate starvation response 1 (PHR1) protein plays central role, which is a key molecular to regulate the expression of a large number of P starvation-responsive genes, such as many Pi transporters (PHTs), induced by phosphate starvation 1 (IPS1), RNS1 (a RNase), and SPX genes by binding to their promoters through the cis-element PHR1-binding sequence (P1BS; GNATATNC) (Rubio et al 2001; Calderón-Vázquez et al 2011; Liu et al 2018; Xu et al 2018). The PHO1 family members, containing both the SPX and EXS domains, involved in Pi loading into the xylem in the long-distance Pi deficiency signalling network (Wang et al 2004; Stefanovic et al 2007; Secco et al 2012). Phytase-overexpressing transgenic maize could improve Pi availability (Chen et al 2008)

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