Chloroplasts in C3 grasses move in response to blue-light

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.

Photosynthetic performance of rocket (Eruca sativa. Mill.) grown under different regimes of light intensity, quality, and photoperiod

“…Often a mixture of red and blue light with a high red to blue light ratio increases the chlorophyll contents in the leaves of the plant due to the activation of the formation of chloroplasts. Krzeszowiec and co-workers [ 44 ] reported that powerful blue light caused chloroplasts to aggregate at cell walls parallel to the light path (avoidance response), while weak blue light caused them to relocate to the most illuminated cell walls (accumulation response).…”

Genome-Wide Identification and Characterization of the CsFHY3/FAR1 Gene Family and Expression Analysis under Biotic and Abiotic Stresses in Tea Plants (Camellia sinensis)

“…As an indispensable environmental factor, light is involved in many biological processes, including plant growth and development, photomorphogenesis, chlorophyll biosynthesis, and chloroplast development [ 1 , 2 ]. In order to ensure their normal growth and development, higher plants have evolved sophisticated and multiple photoreceptors which can sense and adapt to the light environment, such as phytochromes, cryptochromes, phototropins, and ultraviolet-B (UV-B) receptors [ 3 , 4 , 5 ].…”

Blue Light Acclimation Reduces the Photoinhibition of Phalaenopsis aphrodite (Moth Orchid)

“…Phototropins play a key role in the chloroplast movement [ 5 ]. A recent study indicated that blue light induces chloroplast movement in several monocot plants such as Brachypodium , rye, wheat and barley [ 6 ], and Phalaenopsis aphrodite [ 7 ]. If excess light absorption cannot be avoided, the over-excitation of the light-harvesting complex pigments can be alleviated via the dissipation of excess light energy as heat via nonphotochemical quenching (NPQ) and manipulating the photosynthetic efficiency to enhance plant growth and significantly increase crop yield, as has been reported [ 8 , 9 , 10 ].…”