There is a new review paper on carbon isotope discrimination by TPB02 Schön/Avramova.
The carbon isotopic signature of C4 crops and its applicability in breeding for climate resilience.
Stella Eggels, Sonja Blankenagel, Chris-Carolin Schön, Viktoriya Avramova (2021)
In the context of a changing climate, drought is one of the major factors limiting plant growth and yield. Hence, breeding efforts are directed toward improving water use efficiency (WUE) as a key factor in climate resilience and sustainability of crop production. As WUE is a complex trait and its evaluation is rather resource consuming, proxy traits, which are easier to screen and reliably reflect variation in WUE, are needed. In C3 crops, a trait established to be indicative for WUE is the carbon isotopic composition (delta13C) of plant material, which reflects the preferential assimilation of the lighter carbon isotope 12C over 13C during photosynthesis. In C4 crops, carbon fixation is more complex and delta13C thus depends on many more factors than in C3 crops. Recent physiological and genetic studies indicate a correlation between delta13C and WUE also in C4 crops, as well as a colocalization of quantitative trait loci for the two traits. Moreover, significant intraspecific variation as well as a medium to high heritability of delta13C has been shown in some of the main C4 crops, such as maize, sorghum and sugarcane, indicating its potential for indirect selection and breeding. Further research on physiological, genetic and environmental components influencing delta13C is needed to support its application in improving WUE and making C4 crops resilient to climate change.
