RESUMO
BACKGROUND: Eleusine coracana (L.) Gaertn is a crucial C4 species renowned for its stress robustness and nutritional significance. Because of its adaptability traits, finger millet (ragi) is a storehouse of critical genomic resources for crop improvement. However, more knowledge about this crop's molecular responses to heat stress needs to be gained. METHODS AND RESULTS: In the present study, a comparative RNA sequencing analysis was done in the leaf tissue of the finger millet, between the heat-sensitive (KJNS-46) and heat-tolerant (PES-110) cultivars of Ragi, in response to high temperatures. On average, each sample generated about 24 million reads. Interestingly, a comparison of transcriptomic profiling identified 684 transcripts which were significantly differentially expressed genes (DEGs) examined between the heat-stressed samples of both genotypes. The heat-induced change in the transcriptome was confirmed by qRT-PCR using a set of randomly selected genes. Pathway analysis and functional annotation analysis revealed the activation of various genes involved in response to stress specifically heat, oxidation-reduction process, water deprivation, and changes in heat shock protein (HSP) and transcription factors, calcium signaling, and kinase signaling. The basal regulatory genes, such as bZIP, were involved in response to heat stress, indicating that heat stress activates genes involved in housekeeping or related to basal regulatory processes. A substantial percentage of the DEGs belonged to proteins of unknown functions (PUFs), i.e., not yet characterized. CONCLUSION: These findings highlight the importance of candidate genes, such as HSPs and pathways that can confer tolerance towards heat stress in ragi. These results will provide valuable information to improve the heat tolerance in heat-susceptible agronomically important varieties of ragi and other crops.
Assuntos
Eleusine , Termotolerância , Genótipo , Perfilação da Expressão Gênica , Proteínas de Choque TérmicoRESUMO
Severe leaf curl disease of tomato (ToLCD) was noticed recently in the central parts of India and is an emerging threat to the cultivation of tomato. The genomic components of the begomovirus isolate, DNA A and betasatellite associated with ToLCD were cloned by rolling circle amplification method and sequenced. The sequence analysis revealed that the DNA A (2766 nt) of this isolate had the nucleotide identity of >91% with other strains of Tomato leaf curl Karnataka virus (ToLCKV), hence this isolate is proposed as a strain of ToLCKV, named as ToLCKV-Raipur. Similarly, the betasatellite molecule (1355 nt) had the highest identity of 91.1% with Corchorus yellow vein mosaic betasatellite (CoYVMB) and named as CoYVMB-Raipur. The full-length dimerized clones of these two genomic components were agroinoculated on natural (tomato), experimental (Nicotiana benthamiana) hosts and other 20 plant species belong to six different families. The severe leaf curl symptoms appeared only in the hosts, N. benthamiana, and in tomato inoculated with ToLCKV-Raipur alone and ToLCKV-Raipur with CoYVMB-Raipur after 8 and 16-18 days inoculation, respectively. This isolate was also transmissible to healthy tomato plants by whitefly from the tomato plant agroinoculated with ToLCKV-Raipur alone and with CoYVMB-Raipur and produced symptoms within 14-16 days after inoculation. Interestingly, this isolate infects horse gram and chilli by whitefly transmission and both the hosts showed positive for DNA A alone but not for betasatellite. Quantification of the genomic components of this isolate with the agroinoculated N. benthamiana samples by qRT-PCR results showed that the quantity of ToLCKV-Raipur was enhanced by three-fold while inoculated with CoYVMB-Raipur compared to ToLCKV-Raipur alone inoculated plants. However, CoYVMB-Raipur did not enhance the levels of ToLCKV-Raipur in the agroinoculated tomato plants. This is the first evidence of the natural co-occurrence of ToLCKV with betasatellite, CoYVMB causing ToLCD.