Natural variation in the Arabidopsis thaliana root and shoot response to boron deficiency reveals sensitive and responsive phenes and phylogenetic and geographic clustering of boron efficiency adaptations

Abstract

O_LIBoron (B) is an essential plant micronutrient with a crucial role in cell wall stability. To improve plant tolerance to suboptimal B-availability, it is crucial to understand the mechanisms plants have evolved to tolerate B-limited conditions. C_LIO_LIWe assessed temporal physiological, ionomic and molecular responses to B-deficiency across a diversity panel of 185 Arabidopsis thaliana accessions. Plants were characterised in soil-substrate in an automated phenotyping system to track shoot performance, and on agar plates to track root traits. C_LIO_LIAccessions varied widely in their response to B-deficiency. Rosette area decreased by 50% under B-deficiency across all accessions on average but by less than 15% in B-efficient accessions alone. Most root traits suffered under B-deficiency but lateral root length increased in 20% of accessions. The B-uptake and B transporter expression response of B-efficient and B-inefficient accessions was similar, suggesting increased B-use rather than B-uptake efficiency in efficient accessions. Phylogenetic analysis demonstrated enrichment of B-efficient accessions within a clade containing accessions originating from areas characterised as B-deficient. K-means clustering revealed increased lateral root length was associated with efficient shoot growth under B-deficiency. C_LIO_LIThe results demonstrate different response strategies to B-deficiency, indicating target traits to improve the performance of plants grown under B-limiting conditions. C_LI