Inhaling the ent-kaurene in the wilds of Japan

posted May 6, 2014, 8:57 AM by US JSPS Alumni   [ updated Feb 26, 2017, 3:06 PM ]

Author: Sven Nelson

I am a molecular plant scientist. That means that I study plants.  More specifically, I study seeds.  Seeds are an amazing technological advance that plants have developed to protect their seedlings from environmental factors and allow dispersal into the world to optimize the chances of survival of their progeny.  One could refer to seeds as time capsules or space ships, where the infant seedling is protected and sent out into the unknown while it waits for favorable conditions to emerge.  Dry seeds can remain viable for years without water or light and under very low moisture conditions.  One of the major factors that helps the seed decide to get out of the space ship (ie germinate) is a plant hormone called gibberellin, or more commonly GA.  GA stimulates germination of the seed and regulates plant height in the vegetative state.

It is because I study GA that my research has been ever connected to Japan.  GA was first discovered in Japan as the causative agent in a rice disease called 馬鹿苗病 (bakanae-byou), meaning “foolish seedling disease.”  GA is produced by a fungus living on infected rice plants and causes the “foolish seedling” to grow too tall and eventually fall over.  Because of this disease, a lot of the foundational research in GA biosynthesis and signaling occurred in Japan.  Currently, some of the world’s foremost GA researchers are Japanese scientists, which made a JSPS fellowship ideally suited to obtaining my research goals. 

My JSPS fellowship during the summer of 2013 was not my first trip to Japan.  In fact, I worked and lived in Japan for 2 years prior to my entry into graduate school.  During that period, I lived in Hokkaido (北海道), the northern most main island of Japan as an English teacher.  

Those were wonderful days spent in the small town of Furano (富良野市), which is called the “bellybutton” of Hokkaido and even has a bellybutton festival to celebrate the fact that it lies at the center of Hokkaido, just like how your bellybutton lies at the center of your stomach.  For this festival, one dresses in a small skirt-like kimono with a broom handle and gloves for the arms and your stomach exposed.  You cover you head and shoulders with a giant conical hat and your stomach is painted so that it appears to be a giant face on a very short person dancing down the street.  Skilled dancers can undulate their bellies to create facial expression in the painted face that are quite emotive.

The northern land of Hokkaido has hot summers, but nothing like the summers in central Honshu (本州).  My JSPS fellowship took place at the RIKEN institute in Tsurumi (鶴見), which is almost half-way between Yokohama and Tokyo.  The weather in this area is not just hot, but hot and humid.  In fact, perhaps because of these common summertime weather conditions the Japanese language has a specific term  mushiatsui (蒸し暑い) — which incorporates hot and humid into one word.  Every day I would ride the train to get to work, squeezed in like a sardine.  Then I would walk the final leg for about 10-15 minutes and arrive drenched from head to toe.  Over the course of my stay my tolerance to the climate grew until I was able to wander slowly to work carrying my sensu (扇子), or folding fan, and arrive sharing not quite the resemblance to a drowned feline that I had on my initial trips. 

To escape the heat, I traveled with other JSPS fellows to the nearby mountains.  Ajisai (紫陽花) or hydrangeas, grow wild in the forests of Japan and the hike had the added benefit of removing all 108 of my worldly sins.  In Buddhism there are 108 worldly sins or you could say desires/passions.  By choosing the otoko-zaka (男坂) or men's route, and climbing a 108 step stairway — one for each “sin” — I was able to clean my soul a bit.  Interestingly there is also a onna-zaka (女坂) or woman’s route, which did not contain any stairs, either because women do not contain any sins, or because women were considered too delicate to climb 108 stairs.  During the rest of the hike along the side of the trail there were large stone pedestals with giant black spheres affixed at the top and stone wheels below the spheres.  Along the outside edge of one of these wheels were inscribed at various positions around the circumference six characters pertaining to the six human senses: eyes = 眼, ears = 耳, nose = 鼻, mouth = 口, tongue = 舌, and body = 身.  By spinning the wheel at each pedestal you came across you could remove worldly sins associated with that sense.  

Interestingly, along the trail we found that many of the trees were wrapped with rope and paper ornaments.  These are the “Japanese Cedars” (sugi 杉) which are not true cedar trees, but are more closely related to sequoias.  What is particularly curious about these trees is that they emit a compound called ent-kaurene into the air.  This doesn’t have any effect on people, but ent-kaurene is a part of the GA biosynthesis process upstream of GA.  I use mutants in my research which cannot produce GA called ga1-3.  These mutants don’t produce an enzyme at the very beginning of the GA biosynthesis process and therefore require external GA to germinate and grow tall.  However, an alternative to adding GA is to simply grow these seeds next to a Japanese Cedar tree.  They will take up the ent-kaurene from the air — which is downstream of the knocked out enzyme — and can use it to produce their own GA.  This technique is used by many of my Japanese collaborators when growing GA deficient plants, and added a connection back to the lab to my forest meandering.  These trees have religious significance in Japan and are often found either planted or naturally around temples or shrines.  

Truly, there could be no better way to spend a weekend than strolling through the mountains in Japan inhaling the ent-kaurene.  It is one of the fond memories I have from my time as a JSPS fellow and I thought I would share it with you here.  If you have your own memories from Japan to share, please send them to us using the instructions on the Story Submission Page.  We will post one blog-style entry per month selected from those that are submitted.  


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