February 21st, 2015
If someone told you to put your rock hard green McIntosh apple with a banana as that would make it ripe, you sure would scoff a little. But, believe your ears and do that yourself. It’s an easy way to get that red juicy goodness without spending a single penny! It sounds like magic – but it’s pure science. A very recent study by scientists from the Salk institute for Biological Studies have published their finding in the online international journal eLIFE – stating that the plant hormone ethylene alone activates thousand of other genes in a plant.
Ethylene is a gaseous plant hormone that acts at trace levels to stimulate or regulate a variety of processes, including the regulation of plant growth, the ripening of fruit and the shedding of leaves. It is also produced in response to wounding or pathogen attack, exposure to environmental signals such as extreme temperature or drought conditions. All these effects are produced by altering the expression of different genes. Although the effects of ethylene on plants are well documented, much less is known about how its many functions are controlled and coordinated at the molecular level. So how does it work?
It was validated in the model plant Arabidopsis thaliana, by performing molecular level studies to see what happens when it is exposed to ethylene gas? What genes are turned on and what they actually do? It was evidenced that ethylene directly activates a protein, known as EIN3 which is a master regulator in ethylene signaling pathway. Scientists used a technique called ChIP-Seq to identify those regions of DNA where EIN3 binds to. And the number was surprising: over a thousand!
Two interesting things were discovered. First, when EIN3 is activated by ethylene, it activates all those genes that activate its own production. Second, it targets all other hormone signaling pathway in plant because half of the genomic targets of the EIN3 protein were found to be in other hormone signaling pathways.
This clearly shows how ethylene genetically controls the intricate signaling and developmental pathways in the plant. The piece of knowledge generated from this study would help in mapping interconnections between the hormone pathways that have implications on agriculture.
Reference: Katherine Noelani Chang, Shan Zhong, Matthew T Weirauch, Gary Hon, Mattia Pelizzola, Hai Li, Shao-shan Carol Huang, Robert J Schmitz, Mark A Urich, Dwight Kuo, Joseph R Nery, Hong Qiao, Ally Yang, Abdullah Jamali, Huaming Chen, Trey Ideker, Bing Ren, Ziv (2013). Temporal transcriptional response to ethylene gas drives growth hormone cross-regulation in Arabidopsis eLife
ethylene plants,fruit ripening hormone,ethylene in fruit ripening