Sorghum [Sorghum bicolor (L.) Moench] is a fifth most important
cereal crop in the world providing food, fodder/forage
and bio-fuel. The postrainy sorghum crop in India is grown on
residual moisture and inadvertently faces terminal drought.
“Stay-green” (delayed senescence) is a post-flowering drought
tolerance response, which help plants to maintain photosynthetically
active leaf area and continue to fill their grains normally
under stress. Sorghum crop is referred to express functional type of staygreen
and the trait has been mapped to six major QTLs viz.,
Stg1, Stg2, Stg3A, Stg3B, StgC and Stg4. However, the gap in
understanding the key mechanism has not been deciphered
clearly. In this scenario to understand the actual mechanism
of the stay-green pathway the information from different crops
on candidate genes responsible for stay-green phenotype
were considered viz., STAY-GREEN (SGR) along with one or
two homologous (SGR1or NYE1/SGRL); Pheophytin Pheophorbide
Hydrolase (PPH); Pheophorbide a Oxygenase (PAO); Red
Chlorophyll Catabolite Reductase (RCCR); Non-Yellow Coloring
(NYC) and it’s homologous NYC1-Like (NOL); 7-Hydroxymethyl
Chlorophyll a Reductase (HCAR) from Zea mays, Arabidopsis
thaliana and Orzya sativa. Apart from these, senescence associated
genes SAG2, SAG102 and SAG39 were also considered
from Arabidopsis thaliana and Orzya sativa respectively. The sequence
and functional/annotation information for these genes
retrieved for sequence similarity search and it has revealed 45 to
88 % of similarity in sorghum. The mapping of these candidate
gene sequences within the defined QTL regions contributing for
Stay-green has given an insight to utilize the re-sequencing data
for improved drought tolerance in sorghum
