Integrated morphological, physiological, biochemical and transcriptomic analyses elucidate core pathways underlying genotypic differences in drought resistance of perennial grasses

Abstract

Drought stress is the major abiotic factor limiting forage and turf grass growth and productivity. However, systematic studies on the response, adaptation, and molecular mechanisms underlying drought resistance in centipedegrass ( Eremochloa ophiuroides ) remain underexplored. Here, we investigate two centipedegrass genotypes, CG021 and CG101, with significant differences in drought resistance and post-drought recovery capability, by integrating morphological, physiological, biochemical, and transcriptomic analyses. Morphological and physiological analyses showed that drought stress significantly affected growth in both genotypes, including growth performance, chlorophyll content, electrolyte leakage, gas exchange parameters, and osmoprotectant accumulation, with more pronounced effects on CG021. Further results of biochemical analyses demonstrated that compared to CG101, the drought sensitivity of CG021 was associated with excessive chlorophyll degradation (CHLASE, PPH, and CHL-PRX), higher proline and soluble sugar biosynthesis (P5CS, P5CR, SPS, and SS + ), as well as more severe damage to photosynthesis due to carbon assimilation suppression, particularly C 4 pathway (PEPC and PPDK). Furthermore, transcriptome sequencing analyses revealed distinct molecular strategies employed by two genotypes in response to drought stress, with CG101 exhibiting more complex transcriptomic reprogramming, including plant hormones signal transduction, MAPK signaling pathway, and photosynthesis antenna proteins. Notably, differences in drought-responsive genes between two genotypes mainly enriched in photosynthesis pathway, from which three photosynthesis-related genes ( EoPRK1 , EoSPS4 , and EoSUS1 ) were identified as candidate genes likely contributed to the differential drought resistance between CG021 and CG101. These findings revealed the differences in drought response and adaptation strategies between the two centipedegrass genotypes, and highlighted the key regulatory role of photosynthesis in drought resistance of centipedegrass, offering insights into breeding drought resistant varieties in grasses.