No abstract

No abstract

Low light intensity is a great limitation for grain yield and quality in rice. However, yield is not significantly reduced in low light tolerant rice varieties. The work therefore planned for comparative transcriptome profiling under low light stress to decipher the genes involved and molecular mechanism of low light tolerance in rice. At active tillering stage, 50% low light exposure for 1 day, 3 days and 5 days were given to Swarnaprabha (low light tolerant) and IR8 (low light sensitive) rice varieties. Illumina (HiSeq) platform was used for transcriptome sequencing. A total of 6,652 and 12,042 genes were differentially expressed due to low light intensity in Swarnaprabha and IR8, respectively as compared to control. CAB, LRP, SBPase, MT15, TF PCL1 and Photosystem I & II complex related gene expressions were mostly increased in Swarnaprabha upon longer duration of low light exposure which was not found in IR8 as compared to control. Their expressions were validated by qRT-PCR. Overall study suggested that the maintenance of grain yield in the tolerant variety under low light might be results of accelerated expression of the genes which enable the plant to keep the photosynthetic processes moving at the same pace even under low light.

No abstract

Three tropical range grasses (Cenchrus ciliaris, Dichanthium annulatum, and Panicum antidotale) and two range legumes [Macroptilium atropurpureum (siratro) and Stylosanthes hamata (stylo)] were grown under four irradiances, i.e. 100 (I 100 , control), 75 (I 75 ), 50 (I 50 ), and 25 (I 25 ) % of full sunlight. Accumulation of chlorophyll (Chl) b increased but that of Chl a decreased under low irradiances. The greater accumulation of Chl (a+b) in grasses (particularly in D. annulatum and P. antidotale) under shade predicted their shade adaptability. Among legumes Stylosanthes was more adaptive to the shade than Macroptilium due to its higher accumulation of Chl (a+b). Significant difference in the accumulation of carotenoids under I 25 over I 100 was observed in all the species, which shows the increase in quality of the fodder under limited irradiance. There was a significant decrease in soluble protein content in C. ciliaris under I 75 , however, no significant difference in protein content was observed under I 50 and I 25 , which was also reflected in the SDS pattern with the reduction in content of polypeptides at I 75 and following increase at I 50 and I 25 . This was possibly due to reduction of light-induced protein at I 75 and then expression of the stress-induced protein at further reduction of irradiance. Peroxidase activity in C. ciliaris increased with the decrease in irradiance and its isozyme pattern showed differences among all treatments, which indicated the role of different peroxidase isoforms at different irradiances.