Leaf transcriptome profiling of contrasting sugarcane genotypes for drought tolerance under field conditions

Abstract

Drought is the most detrimental abiotic stress to sugarcane production. Nevertheless, transcriptomic analyses remain scarce for field-grown plants. Here we performed comparative transcriptional profiling of two contrasting sugarcane genotypes, ‘IACSP97-7065’ (drought-sensitive) and ‘IACSP94-2094’ (drought-tolerant) grown in a drought-prone environment. Physiological parameters and expression profiles were analyzed at 42 (May) and 117 (August) days after the last rainfall. The first sampling was done under mild drought (soil water potential of −60 kPa), while the second one was under severe drought (soil water potential of −75 kPa). Microarray analysis revealed a total of 622 differentially expressed genes in both sugarcane genotypes under mild and severe drought stress, uncovering about 250 exclusive transcripts to ‘IACSP94-2094’ involved in oxidoreductase activity, transcriptional regulation, metabolism of amino acids, and translation. Interestingly, the enhanced antioxidant system of ‘IACSP94-2094’ may protect photosystem II from oxidative damage, which partially ensures stable photochemical activity even after 117 days of water shortage. Moreover, the tolerant genotype shows a more extensive set of responsive transcription factors, promoting the fine-tuning of drought-related molecular pathways. These results help elucidate the intrinsic molecular mechanisms of a drought-tolerant sugarcane genotype to cope with ever-changing environments, including prolonged water deficit, and may be useful for plant breeding programs.

Drought-triggered leaf transcriptional responses disclose key molecular pathways underlying leaf water use efficiency in sugarcane (Saccharum spp.)

“…Together, these results show the ability of the tolerant genotype to maintain CO 2 assimilation with reduced transpiration – improved WUE – under unfavorable conditions, a strategy that can save water and benefit field-grown plants in the long term. Consistently to other reports ( Sales et al., 2013 ; Contiliani et al., 2022 ), our physiological data support the drought tolerance of the ‘IACSP94-2094’ cultivar.…”

“…Sugarcane ( Saccharum spp. ), a main feedstock for sugar and biofuel production, is strongly impacted during dry summer spells ( de Andrade et al., 2016 ), particularly in marginal or suboptimal areas for cultivation ( Contiliani et al., 2022 ). Sugarcane yields can decrease by up to 70% under water-limiting conditions ( Gosal et al., 2009 ).…”

“…Transcriptional regulation associated with abscisic acid (ABA)-dependent and -independent pathways results in several morphological and physiological changes, such as stomatal closure, antioxidant system activation, and photoassimilate remobilization, among others ( Ferreira et al., 2017 ). Drought-triggered responses are genotype-dependent and can vary contrastingly among sugarcane cultivars ( Rocha et al., 2007 ; Silva et al., 2007 ; Sales et al., 2013 ; Nawae et al., 2020 ; Contiliani et al., 2022 ). For instance, the drought-tolerant sugarcane genotype ‘IACSP94-2094’ displays an enhanced antioxidant system that protects leaf photochemical reactions, ensuring the recovery after drought stress, supporting plant growth after exposure to water deficit ( Sales et al., 2013 ; Contiliani et al., 2022 ).…”

“…Drought-triggered responses are genotype-dependent and can vary contrastingly among sugarcane cultivars ( Rocha et al., 2007 ; Silva et al., 2007 ; Sales et al., 2013 ; Nawae et al., 2020 ; Contiliani et al., 2022 ). For instance, the drought-tolerant sugarcane genotype ‘IACSP94-2094’ displays an enhanced antioxidant system that protects leaf photochemical reactions, ensuring the recovery after drought stress, supporting plant growth after exposure to water deficit ( Sales et al., 2013 ; Contiliani et al., 2022 ). Thus, genotype-comparative studies can help to pinpoint the underlying mechanisms of drought tolerance of stress-resilient genotypes.…”

Transcriptome profiling disclosed the effect of single and combined drought and heat stress on reprogramming of genes expression in barley flag leaf

“…However, in the same study, authors detected both down-and upregulated genes associated with peroxidases in response to aluminum treatment. Such opposite behavior of mentioned genes was also observed in leaves of sugarcane subjected to drought (Contiliani et al, 2022). Contrasting regulation of genes encoding oxidoreductases can be explained by the fact that they constitute a large family of enzymes with complex functions, and apart from defense against stress, they regulate cell homeostasis and plant development (Wang et al, 2018b).…”