TY - JOUR

T1 - Greater mesophyll conductance and leaf photosynthesis in the field through modified cell wall porosity and thickness via AtCGR3 expression in tobacco

AU - Salesse‐Smith, Coralie E.

AU - Lochocki, Edward B.

AU - Doran, Lynn

AU - Haas, Benjamin E.

AU - Stutz, Samantha S.

AU - Long, Stephen P.

PY - 2024/9/30

Y1 - 2024/9/30

N2 - Mesophyll conductance (g m) describes the ease with which CO 2 passes from the sub-stomatal cavities of the leaf to the primary carboxylase of photosynthesis, Rubisco. Increasing g m is suggested as a means to engineer increases in photosynthesis by increasing [CO 2] at Rubisco, inhibiting oxygenation and accelerating carboxylation. Here, tobacco was transgenically up-regulated with Arabidopsis Cotton Golgi-related 3 (CGR3), a gene controlling methylesterification of pectin, as a strategy to increase CO 2 diffusion across the cell wall and thereby increase g m. Across three independent events in tobacco strongly expressing AtCGR3, mesophyll cell wall thickness was decreased by 7%-13%, wall porosity increased by 75% and g m measured by carbon isotope discrimination increased by 28%. Importantly, field-grown plants showed an average 8% increase in leaf photosynthetic CO 2 uptake. Up-regulating CGR3 provides a new strategy for increasing g m in dicotyledonous crops, leading to higher CO 2 assimilation and a potential means to sustainable crop yield improvement.

AB - Mesophyll conductance (g m) describes the ease with which CO 2 passes from the sub-stomatal cavities of the leaf to the primary carboxylase of photosynthesis, Rubisco. Increasing g m is suggested as a means to engineer increases in photosynthesis by increasing [CO 2] at Rubisco, inhibiting oxygenation and accelerating carboxylation. Here, tobacco was transgenically up-regulated with Arabidopsis Cotton Golgi-related 3 (CGR3), a gene controlling methylesterification of pectin, as a strategy to increase CO 2 diffusion across the cell wall and thereby increase g m. Across three independent events in tobacco strongly expressing AtCGR3, mesophyll cell wall thickness was decreased by 7%-13%, wall porosity increased by 75% and g m measured by carbon isotope discrimination increased by 28%. Importantly, field-grown plants showed an average 8% increase in leaf photosynthetic CO 2 uptake. Up-regulating CGR3 provides a new strategy for increasing g m in dicotyledonous crops, leading to higher CO 2 assimilation and a potential means to sustainable crop yield improvement.

KW - AtCGR3 pectin methyltransferase

KW - CO assimilation

KW - carbon isotope discrimination

KW - mesophyll conductance

KW - photosynthetic efficiency

KW - water use efficiency

U2 - 10.1111/pbi.14364

DO - 10.1111/pbi.14364

M3 - Journal article

C2 - 38687118

VL - 22

SP - 2504

EP - 2517

JO - Plant Biotechnology Journal

JF - Plant Biotechnology Journal

SN - 1467-7644

IS - 9

ER -