Tweaking Crassulacean Acid Metabolism (CAM)‐Cycling Plants for Crop Productivity Improvement in View of a Bioenergy Crop,Jatropha curcasLinn

Abstract

Crassulacean acid metabolism (CAM)‐cycling plants display both the C3and CAM photosynthetic pathways at various extents in response to environmental and plant physiological conditions. Evolved from the C3metabolism, CAM is a photosynthetic adaptation specialised to improve plant water‐use efficiency by shifting/extending the CO2uptake from the day to the night. Obligate CAM plants such as the Agave species, pineapples, orchids, and prickly pears are highly productive and respond favourably to extreme heat and drought, and water‐limited environments. In comparison to the C3and C4plants, agricultural CAM crops can thrive in semi‐arid and arid lands, making them an ideal and sustainable commercial crop for food and energy. Very few plants exhibit the CAM‐cycling pathway, while the fairly well‐known examples includeMesembryanthemum crystallinum(ice plant) andJatropha curcas(physic nut). In such plants bestowed with the ability to interchange different photosynthetic metabolisms, little is known on how each unique photosynthetic metabolism is likely to contribute to overall plant growth and development. This article explores the utilisation of CAM for biomass and yield improvement in a bioenergy crop (J. curcas) conferred with CAM‐cycling photosynthetic machinery. TheJ. curcasphotosynthetic‐associated parameters, yield components in relation to transcriptomic data analyses from previous studies are described and discussed to benefit plant breeding programs targeted for productivity enhancement.