Biology subjects

Salas, J. J.

Publications and source records attributed to Salas, J. J..

3 recordsLinked to original sources

bioRxiv2026

NTMC2T5 links lipid homeostasis to plastid differentiation.

Chloroplast biogenesis requires extensive lipid remodeling to establish the internal membrane systems of developing plastids, yet how lipid homeostasis is coordinated during this process remains incompletely understood. Here, we identify a previously unrecognized, Archaeplastida-conserved family of SMP-domain proteins and characterize its role in early plastid development. NTMC2T5 proteins contain an N-terminal chloroplast-targeting membrane region, an SMP domain, and a C2 domain, and localize in punctate patterns at the chloroplast envelope, enriched at regions associated with the endoplasmic reticulum (ER). Loss of NTMC2T5 in Nicotiana benthamiana causes severe defects in chloroplast development during seedling establishment and de-etiolation, whereas chloroplast maintenance in mature leaves is largely unaffected. Ultrastructural analyses revealed that mutant plastids fail to establish normal prolamellar bodies and organized thylakoid membranes, although plastid number and size were largely unaffected. Lipidomic analyses further revealed that NTMC2T5 loss causes a strong reduction in the plastid galactolipids monogalactosyldiacylglycerol and digalactosyldiacylglycerol, accompanied by accumulation of extraplastidial phospholipids and altered fatty-acid composition during de-etiolation. Together, these findings identify NTMC2T5 as a previously unrecognized determinant of lipid homeostasis during plastid differentiation and establish a link between a plant-specific SMP-domain protein family and chloroplast membrane biogenesis. We propose that NTMC2T5 contributes to ER-plastid lipid exchange and/or organization of ER-plastid membrane interfaces during early chloroplast development.

plant biology↗

bioRxiv2025

Uncovering the genetic basis of fruit volatiles in Fragaria vesca through GWAS reveals FvJMT2 as a methyl benzoate biosynthesis gene with insect-repellent function

Strawberry aroma is a key component of fruit quality, influencing consumer preferences and playing important ecological roles, including plant defense. However, the genetic basis of volatile organic compound (VOC) biosynthesis remains only partially understood, particularly in the wild woodland strawberry Fragaria vesca, which has enormous potential to uncover genetic diversity within the genus for improving the commercial strawberries. Here, we performed Genome-Wide Association Studies (GWAS) across a diverse European collection of F. vesca accessions. We identified multiple novel candidate genes involved in the biosynthesis of diverse volatile esters, lactones, terpenoids, and methyl ketones. Among them, we characterized FvJMT2, a SABATH family methyltransferase which we found associated with natural variation in benzenoid esters content. Transient expression in Nicotiana benthamiana and strawberry fruit confirmed its role in methyl benzoate biosynthesis, while enzymatic assays demonstrated that FvJMT2 encodes a promiscuous enzyme capable of methylating not only benzoic acid, but also cinnamic, salicylic, and jasmonic acids. Behavioral assays revealed that methyl benzoate at physiologically relevant concentrations significantly reduced the attraction of Drosophila suzukii flies, supporting a dual role of this VOC in both flavor and pest deterrence. Finally, natural variation analyses in wild Fragaria species and F. x ananassa cultivars showed that benzenoid esters have been largely lost in modern cultivars but retained in ancient and wild accessions. Altogether, this study provides novel insights into the genetics and ecological relevance of strawberry volatiles and identifies candidate loci and alleles for future studies.

genomics↗

bioRxiv2022

The sunflower WRINKLED1 transcription factor regulates fatty acid biosynthesis genes through an AW box binding sequence with a particular base bias

Sunflower (Helianthus annuus L.) is an important oilseed crop in which the biochemical pathways leading to seed oil synthesis and accumulation have been widely studied. However, how these pathways are regulated is less well understood. The WRINKLED1 (WRI1) transcription factor is considered a master regulator in the transcriptional control of triacylglycerol biosynthesis, acting through the AW box binding element (CNTNG(N)7CG) that resides in the promoter of target genes. Here, we identified the sunflower WRI1 gene and characterized its activity in electrophoretic mobility shift assays. We studied its role as a co-regulator of sunflower genes involved in plastidial fatty acid synthesis, identifying genes bound by this transcription factor. Sunflower WRI1-targets included genes encoding all subunits of the pyruvate dehydrogenase complex, the -CT and BCCP genes of the acetyl-CoA carboxylase complex, genes encoding acyl carrier proteins and key genes of the fatty acid synthase complex (KASIII, KASI and KAR), together with the FATA1 gene. As such, sunflower WRI1 regulates seed plastid fatty acid biosynthesis in a coordinated manner, establishing a WRI1 push and pull strategy that drives oleic acid synthesis for its export into the cytosol. We also analyzed the sequence of the functional sunflower AW box, determining the base bias at the N positions in the active sunflower AW box motif. Accordingly, we conclude that the sunflower AW box is sequence-sensitive at the non-conserved positions, enabling WRI1-binding. Moreover, we found that sunflower WRI1 could bind to a non-canonical AW-box motif, opening the possibility of searching for new target genes.

plant biology↗