Root growth and plant height connected to an auxin-related gene

What makes a plant tall? Scientists think it may be connected to a gene involved in responding to the hormone Auxin.

It’s hard to study plant development without coming across auxin somewhere. Auxin is a hormone frequently associated with growth. Auxin response factors (ARFs) as transcription activators or repressors have important roles in plant growth and development, but till now knowledge about them in wheat has been limited. Jingyi Wang and colleagues have now published work on a new ARF in wheat (Triticum aestivum). Their discovery of TaARF4 genes were isolated from wheat and characterized.

Image: Canva.

“TaARF4 overexpression in arabidopsis caused shorter primary root length and PH (plant height(. We propose that this effect occurs by repressing GH3 gene expression to mediate IAA homeostasis. Meanwhile, association analysis results showed that variation in TaARF4-B was significantly associated with root depth and PH. Therefore, TaARF4 may be an important gene resource for regulating wheat growth, and dCAPS markers of TaARF4 might be useful for the selection of wheat genotypes with optimal plant architecture.”

While the discovery gives breeders something to examine in developing new wheat, Wang said that 21st century breeders would not be the first to have exploited TaARF4. “The geographic distribution and allelic frequencies demonstrated that TaARF4-B haplotypes were selected in the history of Chinese wheat breeding.”

It would seem while the gene has been uncovered only recently, there is a long track record of exploiting its value.