scholarly journals Phototropins Mediate Chloroplast Movement in Phalaenopsis aphrodite (Moth Orchid)

2019 ◽  
Vol 60 (10) ◽  
pp. 2243-2254 ◽  
Author(s):  
Yi-Jyun Lin ◽  
Yu-Chung Chen ◽  
Kuan-Chieh Tseng ◽  
Wen-Chi Chang ◽  
Swee-Suak Ko
Keyword(s):  
Blue Light ◽  
Gene Evolution ◽  
Chloroplast Movement ◽  
Close Relative ◽  
Virus Induced Gene Silencing ◽  
Plant Growth And Development ◽  
Moth Orchid ◽  
Chloroplast Movements ◽  
Low Levels ◽  
Phalaenopsis Aphrodite

AbstractChloroplast movement is important for plants to avoid photodamage and to perform efficient photosynthesis. Phototropins are blue light receptors in plants that function in chloroplast movement, phototropism, stomatal opening, and they also affect plant growth and development. In this study, full-length cDNAs of two PHOTOTROPIN genes, PaPHOT1 and PaPHOT2, were cloned from a moth orchid Phalaenopsis aphrodite, and their functions in chloroplast movement were investigated. Phylogenetic analysis showed that PaPHOT1 and PaPHOT2 orthologs were highly similar to PHOT1 and PHOT2 of the close relative Phalaenopsis equestris, respectively, and clustered with monocots PHOT1 and PHOT2 orthologs, respectively. Phalaenopsis aphrodite expressed a moderate level of PaPHOT1 under low blue light of 5 μmol�m−2�s−1 (BL5) and a high levels of PaPHOT1 at >BL100. However, PaPHOT2 was expressed at low levels at <BL50 but expressed at high levels at > BL100. Analysis of light-induced chloroplast movements using the SPAD method indicated that orchid accumulated chloroplasts at <BL10. The chloroplast avoidance response was detectable at >BL25 and significant chloroplast avoidance movement was observed at >BL100. Virus-induced gene silencing of PaPHOTs in orchids showed decreased gene expression of PaPHOTs and reduced both chloroplast accumulation and avoidance responses. Heterologous expression of PaPHOT1 in Arabidopsis phot1phot2 double mutant recovered chloroplast accumulation response at BL5, but neither PaPHOT1 nor PaPHOT2 was able to restore mutant chloroplast avoidance at BL100. Overall, this study showed that phototropins mediate chloroplast movement in Phalaenopsis orchid is blue light-dependent but their function is slightly different from Arabidopsis which might be due to gene evolution.

scholarly journals Spike Activator 1, Encoding a bHLH, Mediates Axillary Bud Development and Spike Initiation in Phalaenopsis aphrodite

2019 ◽  
Vol 20 (21) ◽  
pp. 5406 ◽  
Author(s):  
Yi-Jyun Lin ◽  
Min-Jeng Li ◽  
Hung-Chien Hsing ◽  
Tien-Kuan Chen ◽  
Ting-Ting Yang ◽  
...  
Keyword(s):  
Axillary Bud ◽  
Bhlh Transcription Factor ◽  
Virus Induced Gene Silencing ◽  
Bud Development ◽  
Helix Loop Helix ◽  
Moth Orchid ◽  
Single Spike ◽  
Phalaenopsis Aphrodite ◽  
Spike Initiation ◽  
Gene Expression Levels

Double-spikes Phalaenopsis orchids have greater market value than those with single-spike. In this study, a gene designated as Spike Activator 1 (SPK1), which encodes a basic helix-loop-helix (bHLH) transcription factor, was isolated and characterized from Phalaenopsis aphrodite (moth orchid). SPK1 was highly expressed in the meristematic tissues. In the axillary bud, SPK1 was highly upregulated by a moderately low temperature of 20 °C but downregulated by a spike inhibition temperature of 30 °C. SPK1 protein is localized in the nucleus. Another bHLH, bHLH35, which is also highly expressed in young tissues in the same way as SPK1 was also identified. In contrast to SPK1, bHLH35 transcripts are downregulated at 20 °C but upregulated at 30 °C. Bimolecular florescence complementation assay and yeast two-hybrid assays indicated that SPK1 interacts with bHLH35 and forms a heterodimer. Virus-induced gene silencing (VIGS) showed that 7 out of 15 vector control plants produced double spikes but that only 1 out of 15 VIGS-spk1 plants produced double spikes. RT-qPCR results indicated that VIGS-spk1 downregulated gene expression levels of SPK1, FT, CYCB, and EXPA8. Overall, we propose that SPK1 plays an essential role in early axillary bud development and spike initiation of P. aphrodite.

scholarly journals Plastid Movement Impaired 2, a New Gene Involved in Normal Blue-Light-Induced Chloroplast Movements in Arabidopsis

2006 ◽  
Vol 141 (4) ◽  
pp. 1328-1337 ◽  
Author(s):  
Darron R. Luesse ◽  
Stacy L. DeBlasio ◽  
Roger P. Hangarter
Keyword(s):  
Blue Light ◽  
Chloroplast Movements ◽  
New Gene

scholarly journals Chloroplasts in C3 grasses move in response to blue-light

2020 ◽  
Vol 39 (10) ◽  
pp. 1331-1343 ◽  
Author(s):  
Weronika Krzeszowiec ◽  
Maria Novokreshchenova ◽  
Halina Gabryś
Keyword(s):  
Blue Light ◽  
Higher Plants ◽  
Brachypodium Distachyon ◽  
Photosynthetic Apparatus ◽  
Light Signaling ◽  
Terrestrial Plants ◽  
Energy Capture ◽  
Chloroplast Movements ◽  
C3 Grasses ◽  
The One

Abstract Key message Brachypodium distachyonis a good model for studying chloropla st movements in the crop plants, wheat, rye and barley. The movements are activated only by blue light, similar to Arabidopsis. Abstract Chloroplast translocations are ubiquitous in photosynthetic organisms. On the one hand, they serve to optimize energy capture under limiting light, on the other hand, they minimize potential photodamage to the photosynthetic apparatus in excess light. In higher plants chloroplast movements are mediated by phototropins (phots), blue light receptors that also control other light acclimation responses. So far, Arabidopsis thaliana has been the main model for studying the mechanism of blue light signaling to chloroplast translocations in terrestrial plants. Here, we propose Brachypodium distachyon as a model in research into chloroplast movements in C3 cereals. Brachypodium chloroplasts respond to light in a similar way to those in Arabidopsis. The amino acid sequence of Brachypodium PHOT1 is 79.3% identical, and that of PHOT2 is 73.6% identical to the sequence of the corresponding phototropin in Arabidopsis. Both phototropin1 and 2 are expressed in Brachypodium, as shown using quantitative real-time PCR. Intriguingly, the light-expression pattern of BradiPHOT1 and BradiPHOT2 is the opposite of that for Arabidopsis phototropins, suggesting potential unique light signaling in C3 grasses. To investigate if Brachypodium is a good model for studying grass chloroplast movements we analyzed these movements in the leaves of three C3 crop grasses, namely wheat, rye and barley. Similarly to Brachypodium, chloroplasts only respond to blue light in all these species.

The impact of temperature on blue light induced chloroplast movements in Arabidopsis thaliana

Plant Science ◽  
2015 ◽  
Vol 239 ◽  
pp. 238-249 ◽  
Author(s):  
Justyna Łabuz ◽  
Paweł Hermanowicz ◽  
Halina Gabryś
Keyword(s):  
Arabidopsis Thaliana ◽  
Blue Light ◽  
Chloroplast Movements ◽  
The Impact

scholarly journals A Plant-Specific Protein Essential for Blue-Light-Induced Chloroplast Movements

2005 ◽  
Vol 139 (1) ◽  
pp. 101-114 ◽  
Author(s):  
Stacy L. DeBlasio ◽  
Darron L. Luesse ◽  
Roger P. Hangarter
Keyword(s):  
Blue Light ◽  
Specific Protein ◽  
Chloroplast Movements

scholarly journals Guard-Cell-Specific Expression of Phototropin2 C-Terminal Fragment Enhances Leaf Transpiration

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 65
Author(s):  
Young-Sun Riu ◽  
Hyun-Geun Song ◽  
Hwi-Su Kim ◽  
Sam-Geun Kong
Keyword(s):  
Blue Light ◽  
Guard Cell ◽  
Ectopic Expression ◽  
Stomatal Opening ◽  
Chloroplast Movement ◽  
35S Promoter ◽  
Specific Expression ◽  
Endogenous Expression ◽  
Terminal Fragment ◽  
Leaf Transpiration

Phototropins (phot1 and phot2) are plant-specific blue light receptors that mediate chloroplast movement, stomatal opening, and phototropism. Phototropin is composed of the N-terminus LOV1 and LOV2 domains and the C-terminus Ser/Thr kinase domain. In previous studies, 35-P2CG transgenic plants expressing the phot2 C-terminal fragment–GFP fusion protein (P2CG) under the control of 35S promoter showed constitutive phot2 responses, including chloroplast avoidance response, stomatal opening, and reduced hypocotyl phototropism regardless of blue light, and some detrimental growth phenotypes. In this study, to exclude the detrimental growth phenotypes caused by the ectopic expression of P2C and to improve leaf transpiration, we used the PHOT2 promoter for the endogenous expression of GFP-fused P2C (GP2C) (P2-GP2C) and the BLUS1 promoter for the guard-cell-specific expression of GP2C (B1-GP2C), respectively. In P2-GP2C plants, GP2C expression induced constitutive phototropin responses and a relatively dwarf phenotype as in 35-P2CG plants. In contrast, B1-GP2C plants showed the guard-cell-specific P2C expression that induced constitutive stomatal opening with normal phototropism, chloroplast movement, and growth phenotype. Interestingly, leaf transpiration was significantly improved in B1-GP2C plants compared to that in P2-GP2C plants and WT. Taken together, this transgenic approach could be applied to improve leaf transpiration in indoor plants.

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