綠豆非葉綠色組織之光合作用相關基因的轉錄體分析

Abstract

植物行光合作用主要的器官為葉片，但許多研究指出植物許多呈現綠色的組織也有光合作用能力，這些組織我們稱非葉綠色組織 (non-leaf green tissue, NLGT)。植物仰賴葉片行光合作用提供整個植株利用，然而非葉綠色組織行光合作用大多為提供組織本身需求。我們之前在綠豆不同發育階段的種子測得葉綠素含量及葉綠素螢光Fv/Fm的改變，表示綠豆種子可能具有光合作用能力。因此，本研究想要了解葉片與非葉綠色組織間光合作用基因表現差異。我們首先將綠豆種子作為非葉綠色組織，並以葉片作為對照進行次世代定序。結果顯示種子之種皮及子葉與葉片相比，光合作用及葉綠素代謝相關基因皆表現量下調，但是丙酮酸代謝的相關基因皆顯示上調。之後更進一步比較種子子葉與發芽後子葉的基因表現量差異，結果顯示發芽後子葉光合作用相關基因有較高的表現量。總結上述結果，本研究提供綠豆葉片及種子不同組織之光合作用相關的轉錄組資訊，未來可做為調節非葉綠色組織光合作用效率之應用。

Leaves are the major organ where higher plants perform photosynthesis. Other green tissues, known as non-leaf green tissue (NLGT), also contain photosynthetic activities. Plants rely on leaf photosynthesis to provide utilization of the entire plant, while photosynthesis of NLGT primarily provides the tissue's own needs. Our previous data demonstrated that the chlorophyll content and chlorophyll fluorescence Fv / Fm were changed in the different development stages of mung bean seeds, indicating that seeds may have photosynthesis ability. Therefore, this research aims to understand the expression differences of photosynthesis-related gene between leaf and NLGT. We first performed next-generation sequencing using mung bean seeds and leaves to represent NLGT and control tissue, respectively. The results showed that the expression of photosynthesis- and chlorophyll-related genes were down regulated, whereas that of the pyruvate metabolic genes were up regulated in the seed coat (testa) and cotyledon. Later on, the differences in gene expression between seed cotyledons and germinated cotyledons were compared. The results revealed that the photosynthesis-related genes in the cotyledons after germination had higher expression level. In summary, this study provides transcriptome information regarding photosynthesis in different tissues of mung bean leaves and seeds, which can be used in the future to adjust the photosynthetic efficiency of NLGT.