Biology subjects

Lacchini, E.

Publications and source records attributed to Lacchini, E..

4 recordsLinked to original sources

bioRxiv2026

Cryptic variation alters gene dosage sensitivity to shape inflorescence architecture in tomato

Phenotypic diversity arises in large part from genetic variants at multiple interacting loci, many of which alter gene dosage rather than abolish gene function. Dosage-sensitive variants, which often produce nonlinear phenotypic outcomes, can be exploited to fine-tune quantitative traits for crop improvement using genome editing. However, the phenotypic outcomes of individual variants can differ substantially across genetic backgrounds, as segregating alleles may modulate allelic effects in unexpected ways. Yet, how genetic background shapes gene dosage effects remains underexplored. Here, we show that MADS-box gene dosage effects, which can be used to tune tomato inflorescence architecture for optimal fruit yield, differ profoundly between distinct genetic backgrounds. We mapped the genetic basis of this background dependency and identified the cryptic modifier locus suppressor of branching 2 (sb2), which contains the conserved floral identity gene ANANTHA. We show that natural variation at sb2 modulates how inflorescence architecture responds to MADS-box dosage effects from natural and engineered loss-of-function mutations. Our findings illustrate how cryptic genetic variants can reshape gene dosage relationships and underscore the importance of characterizing such hidden variation for predictive engineering of quantitative traits using genome editing. Significance StatementAdvances in crop genome editing enable precise modifications of gene dosage to fine-tune quantitative traits in crop improvement, but the predictability of such strategies remains limited. We show that hidden genetic differences, known as cryptic variation, can alter how gene dosage changes influence plant growth and development. Using tomato inflorescence architecture as a model, we characterize a natural cryptic modifier locus, suppressor of branching 2 (sb2), that modifies the effects of natural and engineered mutations in dosage-sensitive MADS-box genes. Our findings demonstrate that gene dosage effects depend on genetic background and highlight an often-unrecognized constraint on precision breeding by genome editing. Accounting for similar cases of cryptic variation will be essential for predictable engineering of quantitative traits in crops.

plant biology↗

bioRxiv2025

Discovery of tomato UDP-glucosyltransferases involved in bioactive jasmonate homeostasis using limited proteolysis-coupled mass spectrometry

Jasmonic acid (JA) is the precursor of the bioactive molecule jasmonoyl-isoleucine (JA-Ile), a plant hormone that regulates fitness and development. Although JA biosynthesis, signaling, and responses have been intensively studied, the catabolism of JA remains incompletely understood. Here, we used the recently developed technique of limited proteolysis-coupled mass spectrometry (LiP-MS) to investigate metabolite-protein interactions in plants, aiming to discover enzymes involved in JA metabolism. We identified several previously reported JA-binding proteins, thus validating the robustness of the method, along with recognized enzymes of the JA pathway and a series of novel potential JA-binding proteins. We performed functional characterization of a set of identified JA-interacting UDP-glucuronosyltransferase (UGT) enzymes through omics, biochemical, enzymatic, and structural analyses. Our results demonstrate that two tomato UGTs effectively glucosylate JA to form JA-glucosyl esters, potentially playing a role in the regulation of bioactive JA homeostasis. With this, our findings uncovered a missing step in the metabolism of JA.

plant biology↗

bioRxiv2021

The ALOG family members OsG1L1 and OsG1L2 regulate inflorescence branching in rice

The architecture of the rice inflorescence is an important determinant of seed yield. The length of the inflorescence and the number of branches are among the key factors determining the amount of spikelets, and thus seeds, that will develop. Especially the timing of the identity transition from indeterminate branch meristem to determinate spikelet meristem regulates the complexity of the inflorescence. In this context, the ALOG gene TAWAWA1 (TAW1) has been shown to delay the transition to determinate spikelet development in rice. Recently, by combining precise laser microdissection of inflorescence meristems with RNA-seq we observed that two ALOG genes, Oryza sativa OsG1-like 1 (OsG1L1) and OsG1L2, have an expression profile similar to TAW1. Here we report that osg1l1 and osg1l2 loss-of-function CRISPR mutants have similar phenotypes as the taw1 mutant, suggesting that these genes might act on related pathways during inflorescence development. Transcriptome analysis of the osg1l2 mutant suggested interactions of OsG1L2 with other known inflorescence architecture regulators and the datasets were also used for the construction of a gene regulatory network (GRN) proposing interactions between genes potentially involved in controlling inflorescence development in rice. The spatio-temporal expression profiling and phenotypical analysis of CRISPR loss-of-function mutants of the homeodomain-leucine zipper transcription factor gene OsHOX14 suggest that the proposed GRN indeed serves as a valuable resource for the identification of new players involved in rice inflorescence development. One-sentence summaryOsG1L1 and OsG1L2 control panicle architecture through delaying the transition from indeterminate branch- to determinate spikelet-meristem identity.

developmental biology↗

bioRxiv2020

ER-Anchored Transcription Factors bZIP17 and bZIP60 Regulate Triterpene Saponin Biosynthesis in Medicago truncatula

Triterpene saponins (TS) are a structurally diverse group of metabolites that are widely distributed in plants. They primarily serve as defense compounds and their production is often triggered by biotic stresses through signaling cascades that are modulated by phytohormones such as the jasmonates (JA). Two JA-modulated basic helix-loop-helix (bHLH) transcription factors (TFs), TRITERPENE SAPONIN BIOSYNTHESIS ACTIVATING REGULATOR 1 (TSAR1) and TSAR2, have been previously identified as direct activators of TS biosynthesis in the model legume Medicago truncatula. Here, we report on the involvement of the core endoplasmic reticulum (ER) stress basic leucine zipper (bZIP) TFs bZIP17 and bZIP60 in the regulation of TS biosynthesis. Expression and processing of M. truncatula bZIP17 and bZIP60 proteins was altered in roots with perturbed TS biosynthesis or treated with JA. Accordingly, such roots displayed an altered ER network structure. M. truncatula bZIP17 and bZIP60 proteins were shown to be capable of interfering with the TSAR-mediated transactivation of TS biosynthesis genes, particularly under ER stress conditions, when they translocate from the ER to the nucleus. Furthermore, the inhibitory role of ER stress bZIP TFs in the regulation of JA-dependent terpene biosynthetic pathways appears to be widespread in the plant kingdom, as we demonstrate that it also occurs in the regulation of monoterpene indole alkaloid biosynthesis in the medicinal plant Catharanthus roseus. We postulate that activation of ER stress bZIP TFs provides the plant with a mechanism to balance metabolic activities and thereby adequately govern modulation of growth, development and defense processes in defined stress situations. One sentence summaryER stress bZIP transcription factors can interfere with the activity of jasmonate-inducible bHLH transcription factors to modulate the elicitation of plant specialized metabolism in stress conditions.

plant biology↗