Mechanism of the Mixture of Abscisic Acid and Thidiazuron in Regulating Cotton Leaf Abscission

Morphological analysis and RNA-seq
were conducted to profile the
differentially expressed genes (DEGs) at different time points after
treatment with a mixture of ABA and TDZ (AT), a mixture of TDZ and
diuron (TD), ABA (A), TDZ (T), or water (W). A total of 2805 DEGs
were detected after treatment with A, 18 849 DEGs after treatment
with T, 29 822 DEGs after treatment with AT, and 26 446
DEGs after treatment with TD. GO and KEGG analyses revealed the enrichment
of functional categories, including plant hormone signal transduction
and metabolic pathways, after AT treatment. Ethylene-related genes
(ACO3 and ACS) and cytokinin oxidase/dehydrogenase
(CKX) were upregulated. Cytokinin response regulatory
factors (ARRs) were downregulated, and the cytokinin
content was decreased. Gibberellin-related genes (GIDs) were downregulated, and jasmonic-acid-related genes (JAZ10) were upregulated. The results showed that the interaction between
ethylene and CTK regulated cotton leaf defoliation after AT treatment.
Significantly, gibberellin and jasmonic acid also played a role in
cotton leaf defoliation. The results of this study lay a foundation
for further exploration of the function of ABA and TDZ in regulating
cotton defoliation.