Have We Selected for Higher Mesophyll Conductance in Domesticating Soybean?

Elena A. Pelech, Samantha S. Stutz, Yu Wang, Edward B. Lochocki, Stephen P. Long

Research output: Contribution to journalArticlepeer-review

Abstract

Soybean (Glycine max) is the single most important global source of vegetable protein. Yield improvements per unit land area are needed to avoid further expansion onto natural systems. Mesophyll conductance (gm) quantifies the ease with which CO2 can diffuse from the sub-stomatal cavity to Rubisco. Increasing gm is attractive since it increases photosynthesis without increasing water use. Most measurements of gm have been made during steady-state light saturated photosynthesis. In field crop canopies, light fluctuations are frequent and the speed with which gm can increase following shade to sun transitions affects crop carbon gain. Is there variability in gm within soybean germplasm? If so, indirect selection may have indirectly increased gm during domestication and subsequent breeding for sustainability and yield. A modern elite cultivar (LD11) was compared with four ancestor accessions of Glycine soja from the assumed area of domestication by concurrent measurements of gas exchange and carbon isotope discrimination (∆13C). gm was a significant limitation to soybean photosynthesis both at steady state and through light induction but was twice the value of the ancestors in LD11. This corresponded to a substantial increase in leaf photosynthetic CO2 uptake and water use efficiency.

Original languageEnglish (US)
Pages (from-to)1594-1607
Number of pages14
JournalPlant Cell and Environment
Volume48
Issue number2
Early online dateOct 27 2024
DOIs
StatePublished - Feb 2025

Keywords

  • crop domestication
  • crop improvement
  • food security
  • mesophyll conductance
  • photosynthetic CO assimilation
  • photosynthetic induction
  • soybean
  • water use efficiency

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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