Identification and expression analysis of lncRNAs in rice roots ( Oryza sativa L.) under elevated CO2 concentration and/or cadmium stress

The gradual rise of CO2 is one of the global climate changes, Cd stress is also a major abiotic stress factor that affects rice (Oryza sativa L.). The rice seedlings were treated under two CO2 concentrations and two CdCl2 concentrations for 7 days (treatments names: 400 +/- 20 mu mol mol- 1 CO2 and 0 mu mol L- 1 CdCl2 concentrations, AC; 400 +/- 20 mu mol mol- 1 CO2 and 150 mu mol L- 1 CdCl2 concentrations, Cd; 800 +/- 20 mu mol mol- 1 CO2 and 0 mu mol L- 1 CdCl2 concentrations, EC; 800 +/- 20 mu mol mol- 1 CO2 and 150 mu mol L- 1 CdCl2 concentrations, EC + Cd). The lncRNAs informations were analyzed and excavated using high-throughput sequencing, target genes annotation, and qRT-PCR analysis techniques so as to reveal the regulatory mechanism of lncRNAs in rice roots under high CO2 concentrations and/or Cd stress. The results show that: (1) 326 (AC vs Cd), 331 (AC vs EC), 343 (AC vs EC + Cd), 112 (Cd vs EC + Cd) DE-lncRNAs were identified. (2) MAPK signaling pathway-plant (relevant genes Os04g0534166, Os05g0399800 regulated by MSTRG.18576.11, MSTRG.20864.1) and diterpenoid biosynthesis (relevant genes Os12g0491800, Os02g0570400 regulated by MSTRG.8965.1, MSTRG.11509.1) were annotated in AC vs Cd; Under EC relative to AC, DE-lncRNAs were annotated significantly to the flavonoid biosynthesis (relevant genes Os10g0196100, Os10g0320100, Os11g0116300, Os03g0819600 regulated by MSTRG.4612.1, MSTRG.4668.1, MSTRG.6051.1, MSTRG.16669.1); Under composite treatments, relative to AC, DE-lncRNAs were mainly annotated in the plant hormone signal transduction pathway (relevant genes Os03g0180800, Os03g0180900, Os03g0181100 regulated by MSTRG.13776.1). Under combined treatment, elevated CO2 alleviates Cd stress damage by regulating phenylpropanoid biosynthesis through DE-lncRNAs (relevant genes Os09g0419200 regulated by MSTRG. 29,573.1).