KEY MESSAGE: By measuring the cytokinin content directly and testing the sensitivity to the cytokinin inhibitor @entity5753 , we demonstrated that tasg1 cytokinin metabolism is different from @entity164 . Our previous studies have indicated that compared with @entity164 ( @entity164 ) plants, a @entity3505 stay-green mutant tasg1 exhibited delayed senescence. In this study, we found that the root development of tasg1 occurred later than that of @entity164 . The number of lateral roots was fewer, but the lateral root length was longer in tasg1 than in @entity164 , which resulted in a lower root to shoot ratio in tasg1 than @entity164 . The levels of cytokinin (CK), CK activity, and expression of CK metabolic genes were measured. We found that the total CK content in the root tips and leaf of tasg1 was greater than in @entity164 . The accumulation of mRNA of the CK synthetic gene (TaIPT) in tasg1 was higher than in @entity164 at 9 and 11  days during seedling growth, but the expression of CK oxidase gene (TaCKX) was significantly lower in tasg1. Furthermore, the CK inhibitor @entity5753 was used to inhibit CK activity. When treated with @entity5753 , both the @entity38 content and thylakoid membrane protein stability were significantly lower in tasg1 than @entity164 , consistent with the inhibited expression of senescence-associated genes (TaSAGs) in tasg1. @entity5753 treatment also inhibited the antioxidative capability of @entity3505 seedlings, and tasg1 was more sensitive to @entity5753 than @entity164 , as indicated by the @entity1865 content, protein carbonylation, and antioxidant enzyme activity. The decreased antioxidative capability after @entity5753 treatment may be related to the down-regulation of some antioxidase genes. These results suggest that the CK metabolism was altered in tasg1, which may play an important role in its ability to delay senescence.

The stay-green phenotype of XXXX mutant tasg1 is associated with altered cytokinin metabolism.

@entity5753 :: ('MESH:D008148', 'Chemical') :: ['lovastatin', 'Lovastatin'] @entity164 :: ('MESH:D017827', 'Disease') :: ['WT', 'wild-type'] @entity3505 :: ('4565', 'Species') :: ['wheat'] @entity38 :: ('MESH:D002734', 'Chemical') :: ['chlorophyll'] @entity1865 :: ('CHEBI:566274', 'Chemical') :: ['MDA']
@entity3505 :: (4565,Species) :: ['wheat']
