Dr. Ananda K. Sarkar, Scientist from National Institute of Plant Genome Research (NIPGR) in New Delhi and a specialist in plant stem cells, visited Amrita School of Biotechnology on August 12th and spoke to the students and faculty about his work. In his talk titled, “Regulation of Plant Stem Cells and Meristematic Activity by Related Factors”, Dr. Sarkar discussed various discoveries in Arabidopsis thaliana concerning the interactions between cells in stem cell niches in both shoot and root apical meristems which are essentially responsible for plant growth. In shoots, regulatory cells nearby stem cells express wuschel (WUS) which activates clavata 3 (CLV3) in stem cells resulting in meristem formation. This mechanism is regulated through a negative feedback loop. In roots, WOX5 – a member of the WUS homebox (WOX) family – is actively expressed in the quiescent center.
Along with this, many other factors are expressed in root apical meristems such as short root (SHR), scarecrow (SCR), plethora (PLT), and mIR165/166. Dr. Sarkar also emphasized a surprising finding – that many of the proteins responsible for shoot formation had homologues in root stem cell niches. This gave rise to the understanding that CLV-like molecules help regulate root development.
Through Dr. Sarkar’s enlightening seminar, participants were able to understand on a molecular level how plants are able to grow from stem cell niches in their shoots and roots. Furthermore, Dr. Sarkar’s talk highlighted the importance of understanding plant totipotency – the defining feature of plant “superiority”. This plasticity in plants is attributed to a subset of cells known as stem cells which are self-renewing and can differentiate into any type of plant cell.
We may think that as humans we are superior to all other forms of life on Earth, thanks to a far more advanced intellect. But is it really fair to say that humans are “superior” to other living things? For example, plants, unlike humans, are totipotent, meaning that if any differentiated cell from a plant is taken and culture it in the lab it can actually grow into a new plant complete with a vast array of cell types. This remarkable ability of plants, evolutionarily speaking, may be due to their stationary nature – in order to survive they require an increased plasticity. Imagine trying a similar feat – as much as we try there is no way that we could cut of a limb and have it grow itself into a brand new human!