Editing melon eIF4E associates with virus resistance and male sterility

Abstract

Summary The cap‐binding protein eIF4E, through its interaction with eIF4G, constitutes the core of the eIF4F complex, which plays a key role in the circularization of mRNAs and their subsequent cap‐dependent translation. In addition to its fundamental role in mRNA translation initiation, other functions have been described or suggested for eIF4E, including acting as a proviral factor and participating in sexual development. We used CRISPR/Cas9 genome editing to generate melon eif4e knockout mutant lines. Editing worked efficiently in melon, as we obtained transformed plants with a single‐nucleotide deletion in homozygosis in the first eIF4E exon already in a T0 generation. Edited and non‐transgenic plants of a segregating F2 generation were inoculated with Moroccan watermelon mosaic virus (MWMV); homozygous mutant plants showed virus resistance, while heterozygous and non‐mutant plants were infected, in agreement with our previous results with plants silenced in eIF4E. Interestingly, all homozygous edited plants of the T0 and F2 generations showed a male sterility phenotype, while crossing with wild‐type plants restored fertility, displaying a perfect correlation between the segregation of the male sterility phenotype and the segregation of the eif4e mutation. Morphological comparative analysis of melon male flowers along consecutive developmental stages showed postmeiotic abnormal development for both microsporocytes and tapetum, with clear differences in the timing of tapetum degradation in the mutant versus wild‐type. An RNA‐Seq analysis identified critical genes in pollen development that were down‐regulated in flowers of eif4e/eif4e plants, and suggested that eIF4E‐specific mRNA translation initiation is a limiting factor for male gametes formation in melon.

Mutation of barley HvPDIL5-1 improves resistance to yellow mosaic virus disease without growth or yield penalties

“…For example, knockout variants of the barley host factor gene eIF4E ( Eukaryotic Translation Initiation Factor 4E ) show decreased total grain yield per plant ( Hoffie et al., 2021 ). The loss of function of eIF4E or its isoforms eIF(iso)4E leads to dwarfism or the loss of fertility in Arabidopsis, tobacco, tomato, and melon ( Combe et al., 2005 ; Mazier et al., 2011 ; Callot and Gallois, 2014 ; Patrick et al., 2014 ; Gauffier et al., 2016 ; Pechar et al., 2022 ). Knockout of the powdery mildew susceptibility factor gene MLO ( Buschges et al., 1997 ) in barley or its orthologous gene in wheat results in cell death and early senescence or growth defects in terms of both plant height and grain yield ( Jørgensen, 1992 ; Piffanelli et al., 2002 ; Piffanelli et al., 2004 ; Wang et al., 2014 ).…”

Occurrence, Distribution, and Management of Aphid-Transmitted Viruses in Cucurbits in Spain

“…There are commercially-grown hybrid cultivars of melon with tolerance to aphids, in addition to cultivars carrying the vat gene, which confers resistance to both A. gossypii and the viruses it transmits [ 145 ]. With the means to edit cucurbit genomes directly through the revolutionary CRISPR/Cas9 approach [ 146 ], cucumber lines with mutations that disrupt the eIF4E interaction with viral proteins, which is associated with recessive resistance [ 147 ], have been reported and tested against CVYV, ZYMV, PRSV-W, CMV and CGMMV [ 148 ], and melon lines against MWMV [ 149 ]. This technology is reducing the timeframe needed to obtain cultivars carrying traits of interest and is further underway to incorporate viral disease control into plant crops.…”

AGRICULTURAL DEVELOPMENT BASED ON CRISPR-CAS9 AND RETRONs TECHNIQUES: A PERSPECTIVE APPLICATION ON TOMATO

“…These two reports are the first to apply CRISPR-Cas9 gene-editing technology to generate mutation in the eIF4E1 gene for broad-spectrum resistance to potyvirus. Aside from that, CRISPR/Cas9 application successfully modified eIF4E genes in other crops (Le et al, 2022;Pechar et al, 2022).…”