Understanding Molecular Mechanisms Underlying Sugarcane Roots Response to Aluminum Stress

With the increasing demand for renewable energy, it is predicted that the sugarcane (Saccharum spp.) crop in Brazil will increase significantly and the acreage under sugarcane will enhance from 9.0 to 64 million ha by the years 2018/2019. As a result, more unconventional soils rich in minerals will be brought under cultivation. Aluminum ions (Al+3) together with silicon and iron are the three most abundant mineral elements in soil. Although silicon and iron are required for plant growth, Al is toxic and its bioavailability is highest on acidic soils, resulting in inhibition of root growth and architecture leading to disruption of root elongation. Our goal is to understand the molecular mechanisms of abiotic stress tolerance in sugarcane and the role of miRNA’s in transcriptional regulation. Towards this goal, a relatively tolerant sugarcane cultivar CTC-2 and the susceptible RB855453 cultivar was subjected to Aluminum stress at 221 µMol. RNA-Seq was performed on 12 root samples using 108 bp paired end sequencing on an Illumina HiSeq2500 sequencer. Pairwise comparisons between different treatments in tolerant cultivar identified 16,340 non redundant differentially expressed transcripts (DETs). Functional annotation of DETs revealed that AL+3 tolerance was controlled by several interacting pathways like calcium and G-protein coupled receptor mediated signaling, and regulation by WRKY and R2R3-MYB transcription factors. Some of these genes could be utilized by sugarcane breeders to improve Al+3 stress tolerance in field conditions. Additionally, we have sequenced the miRNAs isolated from root tissues and their interaction with transcripts will be discussed in our presentation.