Interview with Professor Rumi Tominaga
 
Many mysteries have remained unresolved about plant growth mechanisms.
Professor Tominaga works to resolve these mysteries, in view of future applications of these findings.
Deepened understanding of plants will take you to an unseen world.
 
Striving to identify the mechanism of plant epidermal cell differentiation and applying the study results
 
  Dr. Tominaga, an Associate Professor, conducts studies primarily on epidermal cell differentiation in the small flowering plant Arabidopsis thaliana. She is interested in the mechanisms of morphogenesis.

Growth in plants occurs when new cells are produced from meristematic tissues. What attracts her interest is the epidermal cells―the outermost cell layer of tissues produced from these meristematic tissues. The epidermal cells form root hairs, with epidermal cells of leaves and stems differentiating into trichomes. The formation of these root hairs and trichomes involves the expression of specific genes. In this process, the on/off switches for these genes are controlled by proteins called “transcription factors.”
 
Dr. Tominaga explains that, “To put it plainly, meristematic tissues are something like stem cells. The so-called Yamanaka factors, which reprogram animal somatic cells into iPS cells, are also a kind of transcription factor.”

Past studies have found that root hairs and trichomes are regulated by the same transcription factors. Dr. Tominaga’s laboratory pursues research into transcription factors in order to clarify the mechanisms of plant morphogenesis and cell differentiation at the molecular level.
 
She adds that her laboratory has been involved in several world-level discoveries, in a competitive field thronged with researchers around the world.

“Arabidopsis thaliana is often selected as a research material by many researchers, since all its genes have been identified. The CPC gene, which has a function to produce root hairs of Arabidopsis thaliana, was discovered and named by our research group in the past.”

Furthermore, her team discovered a similar gene in tomatoes, and named the gene “SLTRY.” Dr. Tominaga says that she wants to clarify the mechanism for producing root hairs and trichomes so that the findings can be applied to breed a plant that can adapt to the environment. As Dr. Tominaga. says,
 
 
“I think that we may change plant production if we can strengthen their roots. For example, if the form of the root is changed, the plant would become able to absorb water and nutrients more efficiently. Consequently the plant would be better adapted to harsh environments. Other various potential benefits include enhancement of the plant’s growth and resistance to pests and diseases.”
 
Wishing to be a researcher who continues thorough investigation into details to clarify the unknown
 
  According to Dr. Tominaga, due to difficulty in investigating components within soil, no substantial progress has been made in research aimed at producing a more convenient plant by modifying the root form. For this reason, she first focuses on basic research, to pave the way for resolving the mysteries of creating various plant forms.

“Currently, we are analyzing the functions of each individual gene. Through these efforts, we have found that different genes are developed between root-hair cells and hairless cells, and that some transcription factors travel between cells. Recently we have often been engaged in close observations to check if the positional relationship with internal cells determines whether or not root hairs will develop, and to analyze the genes that work under transcription factors.”
 
In addition, Dr. Tominaga’s team uses tomatoes as their research subject, since the scope of applications is limited if using Arabidopsis thaliana alone. Her team is also looking into grapes in joint research with researchers from the University of Miyazaki. Dr. Tominaga says that any of these studies has revealed that genes commonly found in epidermal cell differentiation are related to the formation of fruits and the colors of flowers. This finding indicates the possibility of a new development.
 
Saying “This is also interesting research,” she introduces her study regarding trichomes. In the case of Arabidopsis thaliana, trichomes work only to prevent the plant being eaten by insects with prickles on the leaves. However, trichomes themselves have a function to store important substances―with trichomes of some plants storing essential oils.

She adds, “For example, trichomes of peppermint accumulate mint oils. We are also considering, then, if such a substance-accumulating property of trichomes can be applied to some useful purposes.”

When asked what is the real thrill of her research, she instantly answered saying, “I can now understand what I could not understand before,” indicating her temperament as a researcher by nature.
 
 
Many researchers aim to “figure out the unknown faster than anyone else.” However, Dr. Tominaga admits that to achieve this goal, researchers have to overcome many hardships.
 
Making all-out efforts now—Taking a roundabout course does not matter, since every experience is worthwhile
 

  Looking back on her research career to the present day, Dr. Tominaga says, “I have taken a roundabout course in my life.” This is because, after graduating from the doctoral course of the Graduate School of Biosphere Science at Hiroshima University, she entered the doctoral course of the Graduate School of Agriculture at Kyoto University. The reason, she explains, is as follows:

“When I was in a laboratory at Hiroshima University, I worked under the guidance of Professor Sakurai, who seemed to me to truly enjoy doing research. Inspired by his research attitude, I developed a strong wish to become a professional researcher. In addition, my senior and junior students were all very enthusiastic about their work, which made me aware that I needed to study a lot more to survive as a researcher. That was why I enrolled in the graduate school at Kyoto University to deepen my knowledge about plant genes.”

Regarding such a roundabout course, she says, “A variety of experiences I had accumulated during that time have broadened and enhanced my way of thinking.”

In 2013, she returned to Hiroshima University as an Associate Professor of the Graduate School of Biosphere Science, where she studied in the past. She is now steadily continuing her research, while instructing students, each of whom is assigned to take charge of studying specific genes.

About her students, she comments, “I am aware that I should appropriately educate and foster the next generations. My impression is that students of Hiroshima University are generally serious about their studies. My students are all doing well, though not everyone is the type to work hard and steadily.”

At the end of the interview, Dr. Tominaga gives a message to young people who wish to join this graduate school or pursue a career as a researcher.

“It is difficult to set a future goal and continue efforts to achieve that goal. However, remember that there are many things that can’t be done later if you don’t do it at the present time. I encourage you to make all-out efforts now, to ensure that you won’t regret later. You don’t have to feel depressed even when things don't go the way you plan or want. Failure is an important opportunity to advance to the next step.”
 
Rumi Tominaga
Professor
Laboratory of Plant Environmental Science

Apr. 1, 2001 – June. 30, 2008 Researcher, RIKEN Plant Science Center
July. 1, 2008 – Jan. 15, 2010 Researcher, Laboratory of Plant Organ Morphogenesis, National Institute for Basic Biology
Jan. 16, 2010 – Sep. 30, 2013 Specially-appointed Assistant Professor, Interdisciplinary Research Organization, University of Miyazaki
Oct. 1, 2013 – Mar. 31, 2019 Associate Professor, Graduate School of Biosphere Science, Hiroshima University
Apr. 1, 2019 – present Professor, Graduate School of Integrated Sciences for Life, Hiroshima University

Posted on Aug 18, 2016