These results further suggest that the effects of
brassinosteroids in reducing chlorophyll production are correlated
with down-regulation of LeGLK2 gene expression. These effects also
might be due to the promotion of ethylene synthesis to some extent,
which contributes to expression changes of LePSY1 and LeGLK2.
But according to our investigation, the expression levels of LePSY1
and LeGLK2 changed immediately after brassinolide or brassinazole
treatment, consistent with the expression levels of ethylene
synthesis genes. Related to these, application of brassinolide significantly
promoted lycopene synthesis but suppressed chlorophyll
synthesis via regulating transcript levels of LePSY1 and LeGLK2.
Ethylene plays a critical role in fruit ripening and promotes
the transcription and translation of ripening-related genes.