Transcriptomic analysis of a Sorghum bicolor landrace identifies a role for beta-alanine betaine biosynthesis in drought tolerance

Sorghum’s Whole-Plant Transcriptome and Proteome Responses to Drought Stress: A Review

“…Similar to other transcriptomics studies reviewed above, the significantly enriched transcripts belonged to the following biological processes: response to abiotic stimulus, homeostatic process, regulation of biological quality, cellular homeostasis, and response to stimulus. Similar to reports by Dugas et al [ 88 ] genes involved in the biosynthesis of β-alanine betaine were also up-regulated [ 89 ].…”

“…Transcriptomic studies of sorghum plants under drought stress have also used a broad spectrum of RNA profiling techniques, plant tissues, experimental designs and water stress treatments [ 19 , 73 , 74 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 ], as summarized in Table 2 . Earlier studies investigated a dehydrin mRNA expression pattern in drought-stressed sorghum tissues using Northern blotting and hybridization methods against a 32 P labeled maize dehydrin cDNA probe [ 85 , 86 ].…”

“…Landraces are rich sources of untapped genetic variation that can be harnessed for the development of elite crop cultivars [ 6 ]. Accordingly, Denvarain et al [ 89 ] analyzed changes in the leaf transcriptome of a South African sorghum landrace LR6 in response to water deficits using cDNA microarrays. The plants were exposed to three watering regimes—mild stress, severe stress and re-watering, and all transcripts were compared to those of well-watered controls.…”

“…In summary, sorghum molecular responses to water deprivation involve stress perception/signaling events followed by gene, protein, and metabolite expression changes. The reviewed transcriptomics [ 19 , 73 , 74 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 ] and proteomics [ 71 , 115 , 116 , 117 ] studies also affirm such complexities in drought tolerance mechanisms of the crop. However, because the studies employed a wide range of experimental designs, detailed comparisons between individual drought-responsive genes and proteins are difficult to perform across experiments.…”

“…Although this illustration is not exhaustive, it shows well-known drought-responsive genes/proteins previously identified in Arabidopsis and other plants, including cereals [ 60 , 64 , 65 , 100 ]. Furthermore, the identification of β-alanine betaine biosynthesis enzymes in the sorghum drought-responsive transcriptome [ 88 , 89 ] also provides new insights into the possible functions of this solute in the crop. Beta-alanine betaine in known to accumulate in the stress-tolerant plant family Plumbaginaceae where it possibly serves as an alternative osmoprotectant to glycine betaine under salinity and hypoxic conditions [ 118 , 119 , 120 , 121 ].…”