Expression analysis of tae-miR399 and TaUBC24 at freezing
stress in Dn1
Tillering node is an important organ to winter wheat overwintering (K.
K. Peng et al., 2021). To investigate the changes in tae-miR399 andTaUBC24 expression levels in fields under naturally decreasing
temperature, the qRT-PCR was performed in Dn1 tillering nodes. The
expression of tae-miR399 decreased at 0 ℃ and -10℃ (reached the minimum
at 0 ℃), and then it increased significantly at -25℃ (induced more than
9 folds) (Fig. 2A). The expression of TaUBC24 was opposite to
that of miR399 in tillering nodes, reached the maximum at 0℃ (induced
more than 8 folds), then decreased and peaked the minimum at -25℃ (Fig.
2B).
To eliminate the influence of spatial-temporal differences and other
factors in the field on Dn1 tae-miR399, we conducted qPCR experiments on
the tillering nodes of Dn1 seedlings cultured in the incubator with
short-term freezing treatment. The results showed that the expression
pattern of tae-miR399 was similar to that of the field. During cold
acclimation at 4℃, the expression of miR399 decreased, and then
increased significantly at -10℃ (induced more than 15 folds) (Fig. 2C).
The expression change of its target gene TaUBC24 was still
opposite to the expression change of tae-miR399. It increased
significantly and peaked at 4°C, and then decreased significantly at
-10°C, reaching the lowest peak (Fig. 2D). Based on these results, we
deduced that tae-miR399 played a positive role in achieving plant
tolerance to freezing stress. Meanwhile, from the expression pattern
assays, we speculated that tae-miR399 might regulate TaUBC24expression.