Lignin production associated genes in Cenchrus purpueus

This study aims to reveal genes related to lignin production in Cenchrus purpureus through RNA-Seq. This species is widely used as forrage for cattle, and for the last years, due to its high biomass yield, has been considered as source to lignocellulosic ethanol. Given those two importances, lignin is a molecule related to low digestibility in cattle and recalcitrance in biofuel production. Eight samples were chosen from previous lignin production and forage quality data; four samples had low lignin production, and four had high lignin production. The highest nodes were collected for RNA extraction using TRIzol reagent, following Jordon-Thaden et a;. (2015) protocol. The cDNA library preparation was generated according to Illumina TruSeq Stranded mRNA Sample Prep kit protocol, and RNA sequencing was performed using HiSeq 2500 sequencer. Quality control was measured by FastQC software v 0.11.8. The sequenced reads were aligned to Cenchrus purpureus genome through STAR software v. 2.5.2b (Dobin et al., 2012). After that, the transcriptome was assembled using Stringtie v 2.0.4 software (Pertea et al., 2015). Salmon v 0.7.2 software (Patro et al., 2017) was used to quantify the sequenced reads. The DEG was identified using DESeq2 package, and genes functions were annotated through Trinotate software (Bryant et al., 2017). In total, approximately 130 million reads were sequenced. The final assembled transcriptome was formed by 101,169 transcripts. The differential expressed genes analysis revealed 52 significatively genes. Here, we highlighted genes related to sterol, L-serine and terpene biosynthetic process. We selected four low lignin production samples, and four high lignin production samples, according to previous study from the lab