Molecular Mechanisms Underlying Sugarcane Response to Aluminum Stress by RNA-Seq

Abstract

Sugarcane is an important sugar-source crop. As any other plant, it can be exposed to several abiotic stress conditions. Though some metals contribute to critical physiological processes in plants, the presence of aluminum ions (Al3+) can be very toxic. In order to develop plants that flourish in acidic soils, it is critical to gain insights into the molecular mechanisms of sugarcane response to aluminum stress. To determine the genes involved in sugarcane response to aluminum stress we generated 372 million paired-end RNA sequencing reads, from roots of CTC-2 and RB855453 two contrasting cultivars. Data normalization resulted in 162,161 contigs and 97,335 trinity genes. After the read cutoff, the differentially expressed genes were 4,858 in CTC-2 and 1,307 in the RB855453, Treatment Vs Control, respectively. The differentially expressed genes were annotated into 34 functional categories. The majority of the genes were upregulated in the CTC-2 (tolerant cultivar) and down regulated in RB855453 (sensitive cultivar). Here, we present the first root-transcriptome of sugarcane under aluminum stress. The results and conclusions of this study provide a valuable resource for future genetic and genomic studies in sugarcane. This transcriptome analysis points out that sugarcane tolerance to aluminum may be explained by an efficient detoxification mechanism combined with the lateral root formation and activation of redox enzymes. Following our results, we present here, a hypothetical model for the aluminum tolerance in CTC-2 cultivar.

Physiological, nutritional, and molecular responses of Brazilian sugarcane cultivars under stress by aluminum

“…5C ). Recently, Rosa-Santos et al (2020) reported in (Al-sensitive) and CTC-2 (Al-tolerant) cultivars that genes related to the auxin signaling, detoxification, ROS protection, and signal transduction were significantly involved in sugarcane response roots to Al.…”

“…Differentially regulated genes have been identified in two sugarcane cultivars with more than 4,000 differentially expressed genes (DEGs) in the tolerant cultivar and only about 850 DEGs in the Al sensitive cultivar. Among several transcripts, the ARF ( Auxin responds factor ), MT1 ( metallothionein-like protein 1), CDPK ( calcium-dependent protein kinase ), and Glutathione S-transferases genes were substantially active in Al tolerance mechanisms; ARF was related to auxin signaling, MTI to detoxification, CDPK to signal transduction, and Glutathione S-transferases it ROS protection mechanism ( Rosa-Santos et al, 2020 ).…”

“…Studies on genes related to sugarcane tolerance to Al are scarce ( Drummond et al, 2001 ; Watt, 2003 ). Gene expression patterns are determinants of physiological processes that can modify plants’ cellular properties associated with stress ( Rickes et al, 2019 ; Rosa-Santos et al, 2020 ). Determining gene expression patterns in response to Al stress could improve our understanding of their functions so that we can establish effective strategies to cope with stress conditions.…”

Uncovering the transcriptional response of popcorn (Zea mays L. var. everta) under long-term aluminum toxicity

“…To date, transcriptional expression with RNA sequencing techniques has been used to study Al toxicity tolerance mechanisms in other crops such as sugarcane 29 , buckwheat 30 , and tea plants 31 , allowing the identification of new genes involved in the response to this abiotic stress. The investigation of Al-responsive genes in maize has focused mostly on the early developmental stages and using a microarray approach.…”