ARIBIDOPSIS

In the last post , we talked about a mutant which is unable to form root hair. In contrast, we will go through a mutant which produces too many root hairs.  Myeong Min  Lee and  John  Schiefelbein from the University of Michigan were screening EMS-mutagenized seedlings for abnormal root hair phenotype. They picked up three mutants produce too many root hairs (hairy phenotype) and eventually figured out that these three mutants represent one gene. Due to its "hairy" phenotype, they named it WEREWOLF (WER)!   In the above picture, we can easily compare the hairy phenotype between  wer-1 and wild-type. This name is based on the movie WEREWOLF, where it has a hairy appearance too.  In general, root hair formation is the ideal example of epidermal patterning. In the epidermis, root hair and non-root hair cells are organized one after another. Less or more number of root hair formation represent the aberration of epidermal patter...

Plant development consists of cell division, cell elongation, and differentiation. In the root of model plant Arabidopsis thaliana , we can follow all these three events easily. Cell starts to divide at the meristem, moves out from the meristematic region and then starts to elongate. After entering the maturation zone, it forms root hair and lateral root. Root hair comes first. The place from where we see the root hair, we consider it as maturation zone. Root hairs help to uptake water and ion, anchor and interact with symbiotic microorganisms. If we look at the cross-section of root, the outer most layer is known as the epidermis. This layer has two types of cells: atrichoblast (non-root hair cell) and trichoblast (root hair cell). Only trichoblast produces root hairs. The formation of root hair follows few steps. Firstly, it creates a polar growth zone, popularly knows as "bulge". This "bulge" forms due to the thinning of the cell wall. In the next step, the...

If you don't have clear idea about stoma and pavement cell, I'll request you to go through the following link first.  Mutant Series: SCREAM (SCRM)   Back in 90's, the knowledge about stomatal development and regulation was limited. In the forward genetic approach, we can mutated genes all over the genome in a random fashion. This job is mostly done by E thyl M ethane S ulfonate (EMS). From that randomly mutated population, we screen for our desired traits or phenotypes. In case of stomatal development, if we can find phenotypes containing less or more stoma or abberant pattern.  Ming Yang and Fred D. Sack from Ohio State University took the forward genetic approach to understand the stomatal development. They have found two interetsting mutants: tmm and flp . tmm and flp represent  t oo m any m ouths and f our l i p s , respectively. In case of wild-type plants, we rarely observe two adjacent stomata cells (left panel). In contrast, tmm shows clust...

Find the direction You are out on the street and need to cross the road. The first thing to look is the traffic light. Wating for the green signal. Based on that signal (red/yellow/green), you are going to navigate your direction. Plants need to know the direction like us. Without knowing the direction, it wouldn't be able to navigate to find water, nutrients (down) and sunlight (up). The one universal direction force truth for us and everything else is GRAVITY. Plants have the ability to sense the "gravity" and following the rules of gravity, characteristic known as "gravitropism".  Upon sensing the gravity, plants decide their developmental cues. For instances, plants  increase their apical meristems to higher positions, synthesize tough cell walls to withstand gravitational forces and so on. We call this gravity-based organ development as "gravimorphogenesis".  Apart from gravitropism, Circumnutation  is independent, autonomous movement of...