Year: 2026
Type: preprint
Abstract: Boron toxicity constrains grapevine ( Vitis ) production in irrigated arid and semi-arid regions, yet most available rootstocks are sensitive to excessive boron. Although underutilized Vitis species may harbor sources of adaptation, the genetic basis of natural variation in boron exclusion remains poorly understood, limiting the development of boron-tolerant rootstocks. We screened 267 wild Vitis accessions representing 16 species for their ability to limit leaf boron accumulation under excess boron conditions. Leaf boron concentration varied 190-fold among accessions and was highly heritable (entry-mean H² = 0.71). Its correlation with stomatal conductance was modest (r = 0.34), indicating that transpiration rate explained only a small proportion of the variation in leaf boron accumulation. Leaf boron was correlated with leaf chloride (r = 0.36), but their largely non-overlapping association profiles supported distinct genetic control. Genome-wide association analysis identified a suggestive association on chromosome 11. Independent quantitative trait locus mapping in a full-sib F 1 population (n = 158) derived from Longii-9018 ( V. acerifolia ) × GRN3 (commercial rootstock) identified qBEx11.1 in the same syntenic region on chromosome 11, which explained 19.5% of the phenotypic variance. Positional candidate genes near the association peak included a pectinesterase and a MATE efflux transporter, suggesting roles for cell wall modification and membrane transport. Leaf spectral reflectance was associated with leaf boron concentration in both populations, particularly at visible and red-edge wavelengths, indicating potential for high-throughput phenotyping. Together, these findings identify qBEx11.1 as a priority locus for boron exclusion and support integrated genetic and spectral approaches for breeding boron-tolerant grapevine rootstocks. Plain Language Summary Boron is needed by plants in small amounts, but too much can damage them, especially in dry regions irrigated with boron-rich water. Grapevine rootstocks, the root systems onto which fruiting grape varieties are grafted, may help limit boron uptake. We screened 267 wild grapevines and offspring from two parent vines for their ability to limit boron buildup in leaves. Leaf boron levels differed nearly 190-fold. Genetic analyses of both groups identified the same region of chromosome 11 as important for limiting leaf boron. Transpiration rate explained only a small part of this variation, and boron and chloride buildup appeared to be controlled largely by different genetic factors. Measurements of how leaves reflected light also detected boron-related changes and may allow faster screening. These findings could help breeders develop grapevine rootstocks better suited to boron-affected soils and irrigation water.
Authors: Yaniv Lupo, Sadikshya Sharma, Jose Ramon Munoz, Veronica Nunez, Ana Gaspar, Noe Cochetel, Dario Cantu, Andrew J. McElrone, Luis Diaz-Garcia
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W7220423148