Responses and acclimation to drought and heat stress on Dendrobium Sonia 'Earsakul' and protoplast transient expression system for genome editing studies in Dendrobium

概要

報告番号

※

第

主

号

論

Responses

and

文

acclimation

on Dendrobium Sonia

論文題目

の

要
to

'Earsakul'

旨

drought
and

and

heat

protoplast

stress

transient

expression system for genome editing studies in Dendrobium. (デ
ン ド ロ ビ ウ ム の 乾 燥・高 温 ス ト レ ス に 対 す る 反 応 と 馴 化 お よ び
ゲノム編集研究のためのプロトプラスト一過的発現系の確立）

氏

名

TATICHAROEN Thanachok

論 文 内 容 の 要 旨
The study of CAM response to the drought is well studied, however, response
to high temperature and both stresses combination are still limited. We found that
D endrobium Sonia ‘Earsakul´ showed a very high tolerance to drought stress by
having pseudobulb organ acting as a reservoir to overcome long -term drought
period. The acclimation mechanism was minimizing the stomata opening time only
at optimum duration (phase II; 04.00-06.00) to reduce the water loss by
transpiration, furthermore, PEPC activity increa sed when facing drought to
capture internal CO2 during stomata closed. While high -temperature stress, in the
long term, plants can recover and acclimate to high -temperature stress by opening
stomata wider and longer to minimize the effect of heat stress. A erenchyma
structure was found in pseudobulb tissue which believed it helps alleviate high temperature stress. The stress combination showed the severest symptom both
physical and CER since 7 DAT. The acclimation mechanism showed the same
pattern as drought stress but was unable to soothe the heat stress due to the
limitation of water.
From the response to the stresses, minimizing the irrigation water for

Dendrobium production is required. The reduction of irrigation was done by either
time reduction or changing the irrigation head to a mini springer head and
applying irrigation at a different time of the day. We found that the adjusted
irrigation method can reduce water consumption up to 71 % compared with regular
irrigation. The reduction of water during t he dry season did not affect both growth

and yield in long-term irrigation applications. Irrigation during dawn and evening
time when CAM plants open stomata showed higher total leaf area, leaf fresh and
dry weight compared with common irrigation time of f armer which is during the
morning till noon when CAM plant stomata closed.
For further perspective in terms of breeding technology, CRISPR/Cas9
genome editing is a powerful tool that can achieve the goal by consuming a shorter
time. protoplast transformation by PEG-4000 can shorten the time of testing the
selected vector. Our selected pRGEB32 showed high efficiency and found genome
editing in the protoplast of Dendrobium Formidible which is able to test in PLBs
further. The protoplast extraction in Dendrobium required modification due to the
accumulation of mucilage and crystallization inside the flower tissue.