Petruzzellis, F. | bioRxiv Science

bioRxiv2026

Compost-associated microbiota modulates root transcriptional responses and enhances tomato drought resilience

Compost is a promising sustainable alternative to mineral fertilization because it supplies nutrients and organic matter while hosting diverse microbial communities. However, even if its application to plants has been proven to alleviate different biotic and abiotic stresses, it remains unclear whether its benefits arise from its physico-chemical properties, its associated microbiota, or both. In this study, we compared the impact of compost, sterile compost and an NPK treatment providing equivalent macronutrient inputs on tomato plants cv. Micro-Tom. After assessing physiological parameters of the leaves and molecular responses of the roots under optimal conditions, we performed a drought stress experiment under the three fertilization treatments, complementing the analysis with the investigation of substrate water-retention properties. Although all fertilized treatments improved plant performance relative to nutrient-poor soil, RNA sequencing revealed distinct root transcriptional profiles among compost, sterile compost and NPK, with the compost treatment upregulating several pathways related to plant growth and health, such as hormone signaling, nutrient metabolism, and stress responses. When subjected to severe water stress, compost-treated plants retained the highest photosynthetic efficiency and compost showed the highest available water content compared to the other treatments. These findings suggest that compost may enhance tomato drought resilience through combined effects of substrate water availability and compost-associated microbiota.

plant biology↗

bioRxiv2023

Plant spectral diversity from high-resolution multispectral imagery detects functional diversity patterns in coastal dune communities.

O_LIRemote sensing is a fundamental tool to monitor biodiversity over large spatial extents. However, it is still not clear whether spectral diversity (SD - variation of spectral response across a set of pixels) may represent a fast and reliable proxy for different biodiversity facets such as taxonomic (TD) and functional diversity (FD) across different spatial scales. C_LIO_LIWe used fine resolution (3 cm) multispectral imagery on coastal dune communities in Italy to explore SD patterns across spatial scales and assess SD relationships with TD and FD along the environmental gradient. C_LIO_LIWe measured TD as species richness, while SD and FD were computed using probability densities functions based on pixels and species position in multivariate spaces based on pixel values and traits, respectively. We assessed how SD is related to TD and FD, we compared SD and FD patterns in multivariate space occupation, and we explored diversity patterns across spatial scales using additive partitioning (i.e., plot, transect, and study area). C_LIO_LIWe found a strong correspondence between the patterns of occupation of the functional and spectral spaces and significant relationships were found along the environmental gradient. TD showed no significant relationships with SD. However, TD and SD showed higher variation at broader scale while most of FD variation occurred at plot level. C_LIO_LIBy measuring FD and SD with a common methodological framework, we demonstrate the potential of SD in approximating functional patterns in plant communities. We show that SD can retrieve information about FD at very small scale, which would otherwise require very intensive sampling efforts. Overall, we show that SD retrieved using high resolution images is able to capture different aspects of FD, so that the occupation of the spectral space is analogous to the occupation of the functional space. Studying the occupation of both spectral and functional space brings a more comprehensive understanding of the factors that influence the distribution and abundance of plant species across environmental gradients. C_LI

ecology↗