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

Coralie E. Salesse-Smith, Edward B. Lochocki, Lynn Doran, Benjamin E. Haas, Samantha S. Stutz, Stephen P. Long

Research output: Contribution to journalArticlepeer-review

Abstract

Mesophyll conductance (gm) describes the ease with which CO2 passes from the sub-stomatal cavities of the leaf to the primary carboxylase of photosynthesis, Rubisco. Increasing gm is suggested as a means to engineer increases in photosynthesis by increasing [CO2] 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 CO2 diffusion across the cell wall and thereby increase gm. Across three independent events in tobacco strongly expressing AtCGR3, mesophyll cell wall thickness was decreased by 7%–13%, wall porosity increased by 75% and gm measured by carbon isotope discrimination increased by 28%. Importantly, field-grown plants showed an average 8% increase in leaf photosynthetic CO2 uptake. Up-regulating CGR3 provides a new strategy for increasing gm in dicotyledonous crops, leading to higher CO2 assimilation and a potential means to sustainable crop yield improvement.

Original languageEnglish (US)
Pages (from-to)2504-2517
Number of pages14
JournalPlant Biotechnology Journal
Volume22
Issue number9
DOIs
StatePublished - Sep 2024

Keywords

  • AtCGR3 pectin methyltransferase
  • carbon isotope discrimination
  • CO assimilation
  • mesophyll conductance
  • photosynthetic efficiency
  • water use efficiency

ASJC Scopus subject areas

  • Biotechnology
  • Agronomy and Crop Science
  • Plant Science

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