Profile

I am originally from Nepal. I completed most of my studies in London then came to Leeds to do my PhD, and have stayed here since.

As a football fan, most of my weekends are spent watching football. Other than that I enjoy doing normal things such as socialising with friends and family. I also volunteer as a charity worker and try my best to help people in need.

I often go for a walk if the weather is nice and this is one of the things I saw when I last went for a picnic in the park.

I think that plants are remarkable things – a tiny little acorn seed is capable of growing into a great big oak tree that is around 15 times taller than I am, and that is not even counting how far down its roots grow into the soil.

No matter which way up you plant a seed, the shoot always grows up towards the sky and the root always grow down. Have you ever wondered why this happens?

The research I carried out for my Doctoral studies found that the small molecule TENin1 (TE1) prevents gravity recognition in plants causing them to grow in random directions.

Plant roots have these special gravity sensing cells at the root tip. These gravity sensing cells contain compartments called statoliths (objects that are heavier than the rest of the things in plant cells), and so they sink to the bottom of the cell. This helps plant to know that the bit of the cell where statoliths are sunk is the down direction and the opposite of where they are sunk is the up direction. You can imagine if you put something heavy in a bottle of water it always sinks to the bottom and you would also be able to tell what is up and what is down just by the way it the heavy object sinks.

Plant use this gravity recognition process as a guide to spread the plant growth hormone in different tissues that allows growth to occur. Growth and shape of the plant is determined by the amount of auxin in different plant body part. The root/shoot rip has higher auxin level than the rest of the body. This is where new cells are produced and when these newly produced cells grow longer the plants grow taller pushing the root/shoot tip, deeper into the ground or higher towards the sky, respectively.

Even if plants are tipped over or turned sideways they are able to recognise this by the gravity sensing statoliths as described above. Once they recognise that it is lying sideways, then delivery of auxin inside the cells changes to the new base and this causes the stem to bend upwards and the root bends downwards.

So from the section above we see that the higher amount of auxin in the root tip is necessary to maintain proper growth orientation. Now the question arises how the auxin is shifted around in cells?

Uneven auxin levels is mainly created by the function of a family of proteins, called PIN proteins, whose function is to transport auxin to maintain high level of auxin at the tip of the root and shoot. These PIN proteins are functional at the plasma membrane which is the outer envelope of the cell that encapsulates many different compartments that are known as organelles. PIN proteins are delivered to the plasma membrane in small sub-compartments known as “vesicles” that are derived from established organelles.

Our paper published in the Biochemical Journal shows that TE1 interferes the delivery of PIN proteins by disrupting the complex network of vesicle trafficking, which is responsible for taking PIN proteins to- and back from the plasma membrane.

PIN protein is in the plasma membrane in normal condition (DMSO) but when TE1 is present PIN protein transport to the plasma membrane is blocked so it accumulates in intracellular compartments.

As a consequence, this changes the way auxin is spread inside plants and they are not able to unable to perceive gravity, and at higher TE1 quantity plants are seen to grow at random directions.

This image shows that the amount of Auxin is high at the root tip and slightly less on the sides but when turned sideways auxin moves down (C) but with TE1 it stays same that’s why there is no gravity recognition in plants when treated with TE1.

Vesicles deliver not just PIN proteins but many other important proteins to the plasma membrane and other cellular destination. For example if plants are under pathogen attack, vesicles help deliver defence related-proteins and chemicals that harm pathogens to the pathogen at the attack. Another important function of the vesicles is to deliver dysfunctional protein to a cellular compartment known as vacuole that is especially designated to degrade proteins.

Vesicles are equivalent to cellular postmen that deliver important cargoes to a specific destination

Vesicle trafficking in plants is very similar to that of animals, and faulty protein trafficking system is linked to important human conditions such as Alzheimer’s disease, Huntington’s disease and Parkinson’s disease. Insights gained through fundamental studies that help us understand the cellular protein trafficking pathways in plants not only allows us to engineer better crops but could also provide vital clues into tackling these human conditions.

My hours are very flexible, as long as I get the work done I can come in anytime because I have keys to the lab and 24/7 access to the lab and office. I usually come in to work around 8:30-9:30 and leave around 6:00-6:30.

The first thing I do when I come is to setup experiments that I will carry out throughout the day. Doing experiments is not a constant thing, usually you have to setup an experiments and let the reaction to take place. This is what we call an incubation period, which means there is a lot of waiting time for reaction to happen sometimes for 3 days. So during the free periods I check my emails and check for latest research news, which could directly affect my work.

Then I check other science news and do other activities, such as this, if I have more spare time. I usually have lunch from 12:30-13:30 with work friends when we usually try not to talk about work, then I go back to the lab and setup experiments for the afternoon. I usually have a short tea break around 3:30-4:00 with my work colleagues talking about interesting experiments and developing ideas. Then back to the lab to wrap up the experiments for the day and prepare anything required to do the experiment for the next day. Just before I leave for home around 6:00 I check emails and send any queries.

So it is a fairly relaxed working atmosphere.