Sweet Cherry (Prunus avium L.) PaPIP1;4 Is a Functional Aquaporin Upregulated by Pre-Harvest Calcium Treatments that Prevent Cracking.

Richard Breia,Carlos Conde,Hernâni Gerós,Artur Conde,Andreia F Mósca,Berta Gonçalves,Sofia Correia,Henrique Noronha,Graça Soveral

doi:10.3390/ijms21083017

Abstract

The involvement of aquaporins in rain-induced sweet cherry (Prunus avium L.) fruit cracking is an important research topic with potential agricultural applications. In the present study, we performed the functional characterization of PaPIP1;4, the most expressed aquaporin in sweet cherry fruit. Field experiments focused on the pre-harvest exogenous application to sweet cherry trees, cultivar Skeena, with a solution of 0.5% CaCl2, which is the most common treatment to prevent cracking. Results show that PaPIP1;4 was mostly expressed in the fruit peduncle, but its steady-state transcript levels were higher in fruits from CaCl2-treated plants than in controls. The transient expression of PaPIP1;4-GFP in tobacco epidermal cells and the overexpression of PaPIP1;4 in YSH1172 yeast mutation showed that PaPIP1;4 is a plasma membrane protein able to transport water and hydrogen peroxide. In this study, we characterized for the first time a plasma membrane sweet cherry aquaporin able to transport water and H2O2 that is upregulated by the pre-harvest exogenous application of CaCl2 supplements.

Highlights

Cracking induced by rain significantly limits production of sweet cherry fruits in regions of the world where rainfall occurs just before and during harvest [1]
PaPIP1A;4sincamnabtueresefernu,ittsh. eFuerxtohgeernsotuudsieasppwleicraettihonenodfeCsiagCnle2dutporfeugnucltaitoenda,llbyyc2h-afroalcdt,erthizee ePxapPrIePs1s;i4ontoof tesPtatPhIePh1y;4pionthmesaitsutrheaftrPuaitPs.IPF1u;r4thisear wstuatdeire-spewremreatbhleenadquesaipgonreidn.to functionally characterize PaPIP1;4 to test the hypothesis that PaPIP1;4 is a water-permeable aquaporin
We found that the expression of PaPIP1;4, which is the most expressed aquaporin in cherry tissues [7,23], increased following the application of 0.5% CaCl2

Summary

Introduction

Cracking induced by rain significantly limits production of sweet cherry fruits in regions of the world where rainfall occurs just before and during harvest [1]. Studies on cherry cracking have focused on water movement at the plant and fruit levels [8,9,10], on the mechanisms involved in the deposition and cracking of the cuticle [11,12], and on the strain of the fruit skin [10,13,14,15]. In this regard, the possibility that increased water permeability could be mediated by aquaporins (AQPs) in more susceptible cultivars is a attractive hypothesis. Transcriptomic data in Litchi chinensis suggests that several AQPs are differentially expressed in cracked fruits [16]

Objectives

Methods

Results

Conclusion