Abstract
Transcriptome analysis of sugarcane hybrid CP72-1210 (cold susceptible) and Saccharum spontaneum TUS05-05 (cold tolerant) using Sugarcane Assembled Sequences (SAS) from SUCEST-FUN Database showed that a total of 35,340 and 34,698 SAS genes, respectively, were expressed before and after chilling stress. The analysis revealed that more than 600 genes are differentially expressed in each genotype after chilling stress. Blast2Go annotation revealed that the major difference in gene expression profiles between CP72-1210 and TUS05-05 after chilling stress are present in the genes related to the transmembrane transporter activity. To further investigate the relevance of transmembrane transporter activity against abiotic stress tolerance, a S. spontaneum homolog of a NOD26-like major intrinsic protein gene (SspNIP2) was selected for functional analysis, of which expression was induced after chilling stress in the cold tolerant TUS05-05. Quantitative real-time PCR showed that SspNIP2 expression was increased ~2.5 fold at 30 minutes after cold treatment and stayed induced throughout the 24 hours of cold treatment. The amino acid sequence analysis of the cloned SspNIP2 confirmed the presence of six transmembrane domains and two NPA (Asn-Pro-Ala) motifs, signature features of major intrinsic protein families. Amino acid analysis confirmed that four amino acids, comprising the ar/R (aromatic residue/arginine) region responsible for the substrate specificity among MIPs, are conserved among monocot silicon transporters and SspNIP2. Salinity stress test on SspNIP2 transgenic tobacco plants resulted in more vigorous transgenic lines than the non-transgenic tobacco plants, suggesting some degree of tolerance to salt stress conferred by SspNIP2. SspNIP2-transgenic plants, exposed to 2 weeks of water stress without irrigation, developed various degrees of water stress symptom. The water stress test confirmed that the SspNIP2 transgenic lines had lower evapotranspiration rates than non-transgenic lines, suggesting that SspNIP2 transgenic lines showed a slight tolerance to the early water stress compared to wild type plants.
Highlights
The RNA-Seq analysis revealed that each treatment generated a list of 35,340 and 34,698 Sugarcane Assembled Sequences (SAS) sequences, expressed before and after chilling stress in CP72-1210 and TUS05-05, respectively, which were further analyzed to determine the SAS sequences that were differentially expressed between treatments (Table 2)
It is essential to understand the genetic mechanism of plant response towards abiotic stress, in order to better cope with various stress conditions imposed on crop species
The current study utilized the efficiency of RNA-Seq on gene expression profiling of two Saccharum spp. genotypes, a cold susceptible sugarcane cultivar, CP72-1210, and a cold tolerant S. spontaneum, TUS05-05, in order to investigate Saccharum genes responding to cold stress
Summary
Combining favorable traits from wild species, such as S. spontaneum, into a common sugarcane genotype is certainly desirable to expand the cultivation area, which is restricted to subtropical and tropical regions, despite its tremendous yield potential. This process would improve its cold tolerance, resulting in less energy input, with no genetic modification. Modern commercial sugarcane cultivars (2n = 100–130) are derived from the interspecific hybridization between S. officinarum, which is high in sucrose, and S. spontaneum, tolerant to a broad range of biotic and abiotic stresses, followed by a series of backcrossing with other S. officinarum accessions [2,3,4]. The interspecific hybridization significantly contributed to establish modern sugarcane cultivars, the high degree of polyploidy and the narrow gene pool of modern cultivars imposed difficulties on the effort of sugarcane breeders to develop new sugarcane cultivars with higher yield or enhanced disease resistance
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
