Influence of cultivar and its drought tolerance on soil microbiome

Abstract

Soil microbiome plays a crucial role in plant health and resilience, particularly under abiotic stress conditions such as drought. It is essential to know the influence of grapevine genotype on the composition of this microbiome and to investigate this relationship with plant physiology and adaptation to its environment. This study examines the physiological performance under drought conditions in the field of two grapevine genotypes, ‘Callet’ and ‘Merlot’, grafted onto the same rootstock (R110), along with their associated soil microbiome. ‘Callet’ is a local cultivar known for its superior drought tolerance compared to ‘Merlot’, a widely distributed cultivar. Physiological parameters measured included stem water potential, net photosynthesis, stomatal conductance, and intrinsic water use efficiency. Using 16S rRNA and ITS, microbial diversity was analyzed to assess alpha diversity, beta diversity, and differential abundance of taxa. Statistical analyses, including PERMANOVA and diversity indices (Pielou’s evenness and Faith’s phylogenetic diversity), were employed to assess community composition and response trends. Physiological results corroborated that under drought conditions and without significant differences in soil water content, ‘Callet’ plants exhibited better water status and higher photosynthetic rates than ‘Merlot’ plants. Results also showed that bacterial communities were mainly influenced by genotype, with significant differences observed between ‘Callet’ and ‘Merlot’ grafted onto R110, regardless of water availability. In contrast, fungal communities were affected by the interaction between genotype and drought stress, indicating a more complex response. Furthermore, a significant correlation was found between physiological traits and abundance of some fungal species. For example, an unidentified species of the Herpotrichiellaceae family increases its abundance in drought-affected plants, significantly correlating negatively with photosynthesis and conductance and positively with water use efficiency. Taken together, these results suggest that microbiome composition is driven by shoot genotype and its physiological response to water availability.

Funding

PID2021-125575OR-C21 and PID2021-125575OR-C22 projects funded by MCIN/AEI/10.13039/501100011033/ and FEDER Una manera de hacer Europa. Rodriguez-Izquierdo was funded by PRE2019-088446.