Biology subjects

Vallarino, J. G.

Publications and source records attributed to Vallarino, J. G..

4 recordsLinked to original sources

bioRxiv2026

Multi-omic analysis reveals the genetic architecture of water-deficit stress in Phaseolus vulgaris

Common bean (Phaseolus vulgaris L.) is one of the most important grain legumes for direct human consumption. Currently, 60% of its production is estimated to be at risk due to drought. However, the genetic basis of common beans drought resistance is poorly understood. To this end, we assessed the genetic architecture of drought-responsive changes in a whole genome-sequenced population of 218 common bean accessions. Using multi-omics-based trait evaluation, including lipidomics, photosynthetic and agronomic traits, followed by multi-omics genome-wide association studies (moGWAS), yielded in the detection of a myriad of moQTL for photosynthesis and yield, as well as the levels of various lipids. QTL associated with glycolipids, which are integral to photosynthesis, since they constitute the major membrane components of chloroplasts, were identified. In addition, we molecularly validated several lipid-related candidate genes via P. vulgaris hairy root transformation as well as transient expression in tobacco. In particular, a lipoxygenase and an allene oxide synthase were identified as explaining the variation in triacylglycerol by oxylipin production. These data provide a blueprint for multi-omics-assisted improvement of crop water stress resilience.

plant biology↗

bioRxiv2022

Leaf specific overexpression of a mitochondrially-targeted glutamine synthetase in tomato increased assimilate export resulting in earlier fruiting and elevated yield

To identify potential strategies for increasing the efficiency of tomato leaf metabolism, with a focus on the links between nitrogen/carbon metabolism, we explored a diel Flux Balance Analysis (FBA) model of a source leaf in which the metabolic output was varied up to the theoretically-achievable maximum. We noticed a potentially interesting switch in the use of glutamine synthetase (GS) isoforms -from the chloroplast isoform to the mitochondrial one- for nitrogen assimilation. To further explore this prediction, we characterized transgenic tomato plants over-expressing two tomato GS genes, GS1 and GS2, targeted to mitochondria. Both sets of transgenic plants were characterized as displaying faster growth rate, early flowering and increased fruit yield. In leaves, metabolomic profiling and enzyme activity analysis pointed that GS activity in mitochondrial plays a role in increasing the intracellular synthesis and subsequent export of sugar. Consistent with these changes, higher sucrose concentration in leaf exudates and reduced activities of enzymes involved in leaf starch synthesis were observed. Moreover, mitochondrial GS activity affected chloroplast redox status in a manner that modulated photorespiration and nitrogen metabolism. The combined data reveal the influence of mitochondrial GS activity on both foliar carbon/nitrogen balance and regulation of source-sink metabolism in tomato plants.

plant biology↗

bioRxiv2021

Manipulation of carotenoid metabolism stimulates biomass and stress tolerance in tomato

Improving yield, nutritional value and tolerance to abiotic stress are major targets of current breeding and biotechnological approaches that aim at increasing crop production and ensuring food security. Metabolic engineering of carotenoids, the precursor of Vitamin-A and plant hormones that regulate plant growth and response to adverse growth conditions, has been mainly focusing on provitamin A biofortification or the production of high-value carotenoids. Here, we show that the introduction of a single gene of the carotenoid biosynthetic pathway in different tomato cultivars simultaneously improved photosynthetic capacity and tolerance to various abiotic stresses (e.g., high light, salt, and drought), caused an up to 77% fruit yield increase and enhanced fruits provitamin A content and shelf life. Our findings pave the way for developing a new generation of crops that combine high productivity and increased nutritional value with the capability to cope with climate change-related environmental challenges.

plant biology↗

bioRxiv2020

Allelic Variation of MYB10 is the Major Force Controlling Natural Variation of Skin and Flesh Color in Strawberry (Fragaria spp.) fruit

Anthocyanins are the principal color-producing compounds synthesized in developing fruits of strawberry (Fragaria spp.). Substantial natural variation in color have been observed in fruits of diploid and octoploid accessions, resulting from distinct accumulation and distribution of anthocyanins in fruits. Anthocyanin biosynthesis is controlled by a clade of R2R3 MYB transcription factors, among which MYB10 has been shown as the main activator in strawberry fruit. Here, we show that MYB10 mutations cause most of the anthocyanin variation observed in diploid woodland strawberry (F. vesca) and octoploid cultivated strawberry (F. xananassa). Using a mapping-by-sequencing approach, we identified a gypsy-transposon insertion in MYB10 that truncates the protein and knocks out anthocyanin biosynthesis in a white-fruited F. vesca ecotype. Two additional loss-of-function MYB10 mutations were identified among geographically diverse white-fruited F. vesca ecotypes. Genetic and transcriptomic analyses in octoploid Fragaria spp. revealed that FaMYB10-2, one of three MYB10 homoeologs identified, residing in the F. iinumae-derived subgenome, regulates the biosynthesis of anthocyanins in developing fruit. Furthermore, independent mutations in MYB10-2 are the underlying cause of natural variation in fruit skin and flesh color in octoploid strawberry. We identified a CACTA-like transposon (FaEnSpm-2) insertion in the MYB10-2 promoter of red-fleshed accessions that was associated with enhanced expression and anthocyanin accumulation. Our findings suggest that putative cis regulatory elements provided by FaEnSpm-2 are required for high and ectopic MYB10-2 expression and induction of anthocyanin biosynthesis in fruit flesh. We developed MYB10-2 (sub-genome) specific DNA markers for marker-assisted selection that accurately predicted anthocyanin phenotypes in octoploid segregating populations.

plant biology↗