Transcriptome Profile of the Variegated Ficus microcarpa c.v. Milky Stripe Fig Leaf

Abstract

Photosynthetic properties and transcriptomic profiles of green and white sectors of Ficus microcarpa (c.v. milky stripe fig) leaves were examined in naturally variegated plants. An anatomic analysis indicated that chloroplasts of the white sectors contained a higher abundance of starch granules and lacked stacked thylakoids. Moreover, no photosynthetic rate was detected in the white sectors. Transcriptome profile and differential expressed gene (DEG) analysis showed that genes encoding PSII core proteins were down-regulated in the white sectors. In genes related to chlorophyll metabolism, no DEGs were identified in the biosynthesis pathway of chlorophyll. However, genes encoding the first step of chlorophyll breakdown were up-regulated. The repression of genes involved in N-assimilation suggests that the white sectors were deprived of N. The mutation in the transcription factor mitochondrial transcription termination factor (mTERF) suggests that it induces colorlessness in leaves of the milky stripe fig.

Protective Role of Leaf Variegation in Pittosporum tobira under Low Temperature: Insights into the Physio-Biochemical and Molecular Mechanisms

“…We also observed an abundance of starch granules in the yellow sector as compared to the green sector, suggesting that the yellow sectors are nutrient sinks because they are unable to perform photosynthesis. Similar conclusions were previously reported in different species including variegated Arabidopsis [1,35,36], tobacco [37], begonia [6] and fig [3]. However, the photosynthetic efficiency was not obviously affected in “Variegatum” (Figure 3), contrasting with the reports that leaf variegation affects photosynthetic efficiency [12].…”

“…TEM analysis was performed as described by Shih et al [3]. Green and yellow sectors of leaves were cut into small cubes in the field and placed in a fixation solution containing 2.5% glutaraldehyde and 4% paraformaldehyde in 0.1 M sodium phosphate buffer (pH 7.0).…”

“…Leaf variegation has been observed in many species of higher plants [1,2,3] and this special attractive trait has become a focus of plant breeding as it increases the economic value of ornamental plants [4]. There are two categories of leaf variegation in plants: structural-related variegation and pigment-related variegation [5,6].…”

“…Furthermore, the chlorophyll-deficient leaf-mutant also showed the expressional repression of transcriptional factors GLK1 , Ftsz and MinD that regulate chloroplast development and division [15]. Recently, a mutation in the transcription factor mitochondrial transcription termination factor ( mTERF ) has been found to induce colorlessness in leaves of variegated fig [3]. Although these studies have provided a deep understanding of the variegation mechanism in plants, the advantage of this trait for the good fitness or for the plant physiology is still poorly understood.…”

Functional analysis of mTERF5 and mTERF9 contribution to salt tolerance, plastid gene expression and retrograde signalling in Arabidopsis thaliana

“…) and colourless of white leaf sectors in the second (Shih et al . ). Therefore, both the mTERF5 and mTERF9 loss‐ and gain‐of‐function can alter expression of nuclear and plastid genes, which supports the important role of both genes in OGE and, consequently, in plant development.…”