Biology subjects

Capparotto, A.

Publications and source records attributed to Capparotto, A..

4 recordsLinked to original sources

bioRxiv2025

A symbiotic MLO gene regulates root development via RALF34-triggered Ca2+ signalling in Lotus japonicus

Mildew Locus O (MLO) genes, initially identified as powdery mildew susceptibility factors, are increasingly recognized as multifunctional regulators implicated in diverse processes, including plant reproduction, root thigmotropism, and interactions with beneficial microbes. Recent evidence shows that MLO proteins can act as Ca2+-permeable channels in response to Rapid Alkalinization Factors (RALF) peptides in reproductive cells, pointing to broader roles in Ca2+-mediated signalling. In this study, we investigate the symbiotic clade IV member LjMLO4 in the model legume Lotus japonicus, focusing on its role in root development and responsiveness to LjRALF34 peptides. We show that LjMLO4 expression is strongly induced in root cells colonized by arbuscular mycorrhizal (AM) fungi, yet loss-of-function mutants exhibit only subtle AM-associated phenotypes. Instead, we uncover a previously uncharacterized function of LjMLO4 as a regulator of primary root growth and lateral root formation, acting even in the absence of AM fungal colonization and in a Ca2+-dependent manner. Heterologous expression in E. coli confirms that LjMLO4 facilitates Ca2+ transport, while genetic and physiological assays demonstrate its contribution to LjRALF34-triggered root growth responses and Ca2+ signalling. Together, these findings identify LjMLO4 as a molecular hub between peptide signalling, Ca2+ transport and root system architecture, highlighting how MLO proteins integrate developmental, nutritional and symbiotic cues.

plant biology↗

bioRxiv2025

Plant genetic and root-associated microbial diversity modulate Lactuca sativa responsiveness to a soil inoculum under phosphate deficiency

O_LIMicrobial-based approaches have been proposed as a solution to decrease the use of chemical fertilizers in agriculture. Among these, the most promising candidates are arbuscular mycorrhizal fungi (AMF), with their ability to extend the root surface and absorb phosphate, and phosphate solubilizing bacteria (PSB), but their effectiveness has been shown to depend on plant genetic diversity. C_LIO_LIWith the aim of identifying genetic markers explaining plant differential responses to soil-beneficial microbes, we monitored a panel of 128 fully sequenced varieties of Lactuca sativa under controlled P starvation conditions, treated with AMF and PSB. C_LIO_LIResults showed a strong effect of the lettuce genetic variation on the plant physiological and morphological response to the inoculum. Through genome-wide association studies, we identified specific genetic regions associated with variations in leaf phosphate and shoot biomass in response to the treatment. C_LIO_LIBeyond genetic factors, we detected changes in fungal {beta}-diversity and increases in bacterial -diversity associated with phenotypic variation, and we identified 44 ASVs linked to variation in agriculturally important traits. Among these, we experimentally validated the role of six bacterial strains through both in vitro and pot experiments, in affecting the leaf phosphate concentration and plant shoot biomass. C_LIO_LIIn conclusion, we highlighted key genetic and physiological mechanisms that could play a crucial role in enhancing microbial treatments for optimizing plant phosphate management. C_LI

plant biology↗

bioRxiv2024

Modulatory effect of plasma-activated water on arbuscular mycorrhizal symbiosis in Lotus japonicus

Plasma-activated water (PAW) is a recently developed cutting-edge technology that is increasingly gaining interest for its applications in medicine, food industry and agriculture. In plant biology, PAW has been shown to promote seed germination, plant growth, and plant resistance to biotic and abiotic stresses. Despite increasing knowledge of the beneficial effects exerted by PAW on plants, little information is currently available about how this emerging technology may affect the mutualistic plant-microbe interactions in the rhizosphere. In this work we have investigated the impact of irrigation with PAW, generated by a plasma torch, on arbuscular mycorrhizal (AM) symbiosis between the model legume Lotus japonicus and the AM fungus Rhizophagus irregularis. Since PAW sensing by plants has recently been demonstrated to occur through calcium-mediated signalling, we monitored early cellular responses to different doses of PAW in L. japonicus roots expressing the Ca2+-sensitive photoprotein aequorin targeted to either the cytosol or nucleus. Quantitative analyses of AM fungal accommodation in host roots along with phosphate accumulation in leaves, as well as chemical analysis of N, C, S in shoots, showed that treatments with PAW play a modulatory role on plant AM symbiotic performance, in a manner dependent on the time interval of water exposure to the plasma and on the duration of plant irrigation treatment with PAW. Establishing a solid scientific ground for plasma-related technology may provide key elements to develop tools and treatments aimed to increase crop plant yield in a sustainable manner.

plant biology↗

bioRxiv2024

Plant phenotypic differentiation outweighs genetic variation in shaping the lettuce leaf microbiota

Lettuce is a widely consumed raw vegetable, making it crucial to understand and predict its leaf-associated microbial communities for the benefit of both plant and human health. While environmental factors are known to strongly influence plant leaf microbiomes, the role of plant-specific determinants in shaping microbial diversity remains unclear. In this study, we investigated the impact of three key plant factors -genetic distance, morphology and leaf micro- and macronutrient content- on the composition and diversity of lettuce leaf bacterial communities. Using 131 fully-sequenced Lactuca sativa genotypes, we analyzed their leaf-associated bacterial communities via 16S rRNA amplicon sequencing. Our findings revealed that morphological classification, as defined by breeders, exerts a greater influence on bacterial community diversity than genetic distance or variations in leaf nutrient levels. Together with shoot traits they explained 13.9% of the observed bacterial diversity. Further analysis of 10 specific leaf morphological traits showed that heart formation, head height, and venation types significantly shaped bacterial richness and evenness, mainly acting on non-hub members. The strong association between leaf morphology and bacterial community structure suggests that phenotypic traits play a disproportionately large, yet understudied, role in leaf microbiota establishment offering new potential for manipulation by breeders.

plant biology↗