A wheat/rye polymorphism affects seminal root length and yield across different irrigation regimes

HOWEL TYSON; MORICONI JI; XUEQIANG ZHAO; JOSHUA HEGARTY; TZION FAHIMA; GUILLERMO E. SANTA-MARIA; JORGE DUBCOVSKY

JOURNAL OF EXPERIMENTAL BOTANY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2019 vol. 70 p. 4027 - 4037

0022-0957

Theintrogression of a small segment of wheat (Triticum aestivum L.)chromosome arm 1BS in the distal region of rye (Secale cereale L.)1RS.1BL arm translocation in wheat (henceforth 1RSRW) was previously associated with reduced grain yield,carbon isotope discrimination and stomatal conductance, suggesting reducedaccess to soil moisture. Here we show that lines with the normal 1RS arm havelonger roots than lines with the 1RSRW arm in bothfield and hydroponic experiments. In the 1RSRW lines,differences in seminal root length were associated with a developmentallyregulated arrest of the root apical meristem (RAM). Approximately 10 days aftergermination, the seminal roots of the 1RSRW plants showeda gradual reduction in elongation rate, and stopped growing a week later.Seventeen days after germination, the roots of the 1RSRW plants showed altered gradients of reactive oxygen speciesand emergence of lateral roots close to the RAM, suggesting changes in the rootmeristem. The 1RSRW lines also showed reducedbiomass (estimated by Normalized Differences Vegetation Index) and grain yieldrelative to the 1RS lines, with larger differences under reduced or excessiveirrigation than under normal irrigation. These results suggest that thisgenetic variation could be useful to modulate root architecture.