Different adaptation strategies of two citrus scion/rootstock combinations in response to drought stress

Abstract

Scion/rootstock interaction is important for plant development and for breeding programs. In this context, polyploid rootstocks presented several advantages, mainly in relation to biotic and abiotic stresses. Here we analyzed the response to drought of two different scion/rootstock combinations presenting different polyploidy: the diploid (2x) and autotetraploid (4x) Rangpur lime (Citrus limonia, Osbeck) rootstocks grafted with 2x Valencia Delta sweet orange (Citrus sinensis) scions, named V/2xRL and V/4xRL, respectively. Based on previous gene expression data, we developed an interactomic approach to identify proteins involved in V/2xRL and V/4xRL response to drought. A main interactomic network containing 3,830 nodes and 97,652 edges was built from V/2xRL and V/4xRL data. Exclusive proteins of the V/2xRL and V/4xRL networks (2,056 and 1,001, respectively), as well as common to both networks (773) were identified. Functional clusters were obtained and two models of drought stress response for the V/2xRL and V/4xRL genotypes were designed. Even if the V/2xRL plant implement some tolerance mechanisms, the global plant response to drought was rapid and quickly exhaustive resulting in a general tendency to dehydration avoidance, which presented some advantage in short and strong drought stress conditions, but which, in long terms, does not allow the plant survival. At the contrary, the V/4xRL plants presented a response which strong impacts on development but that present some advantages in case of prolonged drought. Finally, some specific proteins, which presented high centrality on interactomic analysis were identified as good candidates for subsequent functional analysis of citrus genes related to drought response, as well as be good markers of one or another physiological mechanism implemented by the plants.

Intermediate Inheritance with Disomic Tendency in Tetraploid Intergeneric Citrus × Poncirus Hybrids Enhances the Efficiency of Citrus Rootstock Breeding

“…The tetraploid Carrizo citrange appears to be less sensitive to boron excess than the corresponding diploid [24]. Transcriptome studies revealed constitutive overexpression of genes involved in stress response in tetraploid citrus compared to their diploid parents [18,19,25].…”

“…Under salinity stress or water deficit, tetraploid seedlings were shown to be more tolerant than their parental diploid counterparts [12][13][14][15][16][17]. Increased tolerance was also observed when rootstock was grafted [18][19][20]. Better tolerance to cold was reported in clementine trees grafted onto tetraploid Carrizo citrange [21].…”

Genome of a citrus rootstock and global DNA demethylation caused by heterografting

“…In the citrus industry, the use of suitable rootstocks plays a very important role in commercial citrus production. The rootstock has a significant impact on plant vigor, yield, fruit quality, and disease resistance 24 – 27 . Additionally, the rootstock can also affect the metabolome of citrus fruit juice, which determines the flavor and nutrition of the fruit 3 , 28 .…”

Preferential Homologous Chromosome Pairing in a Tetraploid Intergeneric Somatic Hybrid (Citrus reticulata + Poncirus trifoliata) Revealed by Molecular Marker Inheritance

“…In citrus, polyploidy has been described to improve adaptation to different stresses and resilience ( Mouhaya et al, 2010 ; Podda et al, 2013 ; Allario et al, 2013 ; Tan et al, 2015 ; Tan et al, 2017 ; Dutra de Souza et al, 2017 ; Oliveira et al, 2017 ; Oustric et al, 2017 , 2018 ), and several teams worldwide have been developing rootstock breeding at the tetraploid level ( Grosser and Chandler, 2000 ; Grosser et al, 2000 , 2015 ; Ollitrault et al, 2000 , 2007 ; Guo et al, 2007 ; Grosser and Gmitter, 2010 ; Dambier et al, 2011 ; Guerra et al, 2016 ). Many of these programs focus on combinations of Citrus species with Poncirus , a related genus.…”