Review of Gibberellin Signaling

Abstract

This review covers recent advances in gibberellins(GA) signaling. Hormones gibberellins (GAs) are a class of diterpenoid acids that control many aspects of plants' life, including both developmental processes and stress responses. Nowadays, we have a good understanding of how GA levels are regulated and how this information is translated into physiological responses, mainly through genetic and biochemical approaches carried out during the last two decades in rice and Arabidopsis. Here, we review the current knowledge of the GA signaling, pathway from GA metabolism to the downstream responses and pay special attention to the regulatory molecular mechanisms. GA biosynthesis starts in plastids, whereas it's last steps, and also the GA inactivation, takes place in the cytosol. Importantly, the expression of gene coding enzymes that catalyze limiting steps, for example, the soluble GA 20-oxidases, is usually regulated by environmental cues, making the GA level very sensitive to changes in the environment. The binding of the hormone to the GID1 receptor provokes the degradation of the master negative regulators in the pathway, the transcriptional regulators DELLA proteins, and GA-promoted responses proceed. The biochemical basis of the GID1-GA-DELLA regulatory module is well established, but how DELLA proteins regulate downstream events is a matter of current intensive research. In this regard, the regulation of transcription factors' activity through direct physical interaction seems to be an extended yet not unique mechanism of DELLA action. Finally, how all this wealth of information is being used with biotechnological purposes is revised.

Response Of Papaya (Carica papaya L.) Seeds Growth To The Gibberellin (GA3) and Cow Biourine

“…High application of gibberellic acid (GA3) can lead to decreased transcription of GA20 oxidase which is the main target in feedback regulation. If the transcription of GA20 oxidase decreases, there will be a blockage of GA3 biosynthesis so that the activity of gibberellic acid decreases (Degefu & Tesema, 2020). When the activity of gibberellic acid decreases, there is a decrease in cell division and growth and protein synthesis.…”