Effects of Light-Emitting Diode Irradiation on Growth Characteristics and Regulation of Porphyrin Biosynthesis in Rice Seedlings

Abstract

Abstract:We examined the effects of light quality on growth characteristics and porphyrin biosynthesis of rice seedlings grown under different wavelengths from light emitting diodes (LEDs). After 10 days of exposure to various wavelengths of LEDs, leaf area and shoot biomass were greater in seedlings grown under white and blue LEDs than those of green and red LEDs. Both green and red LED treatments drastically decreased levels of protoporphyrin IX (Proto IX) and Mg-porphyrins compared to those of white LED, while levels of Mg-Proto IX monomethyl ester and protochlorophyllide under blue LED were decreased by 21% and 49%, respectively. Transcript levels of PPO1 were greatly upregulated in seedlings grown under red LED compared to white LED, whereas transcript levels of HO2 and CHLD were upregulated under blue LED. Overall, most porphyrin biosynthetic genes in the Fe-porphyrin branch remained almost constant or upregulated, while most genes in the Mg-porphyrin branch were downregulated. Expression levels of nuclear-encoded photosynthetic genes Lhcb and RbcS noticeably decreased after exposure to blue and red LEDs, compared to white LED. Our study suggests that specific wavelengths of LED greatly influence characteristics of growth in plants partly through altering the metabolic regulation of the porphyrin biosynthetic pathway, and possibly contribute to affect retrograde signaling.

Photosynthetic characteristics and chloroplast ultrastructure of welsh onion (Allium fistulosum L.) grown under different LED wavelengths

“…1b). This may have been due to the responses of the leaves to different optical signals, which is consistent with the results of previous studies on rice and lettuce [39,40]. However, studies have shown different results for Camptotheca acuminata Decne.…”

Quantifying risk factors associated with light-induced potato tuber greening in retail stores

“…This may be attributed to the broad-band light filters used in earlier studies, which could transmit a mixture of wavelengths that may have confounded results. The intense greening at blue wavelengths observed in this study is consistent with previous studies in leaf tissues, which showed enhanced activity of key chlorophyll enzymes [16,17], leading to higher chlorophyll accumulation as compared to red light [18][19][20][21].…”

Blue and Red LED Illumination Improves Growth and Bioactive Compounds Contents in Acyanic and Cyanic Ocimum basilicum L. Microgreens

“…In Chinese cabbage, red:blue 6:1 and blue light increased chlorophyll concentrations significantly, while red light decreased chlorophyll accumulation as a result of reductions in chlorophyll precursors ALA, Proto IX, Mg-Proto IX and protochlorophyllide [ 32 ]. In rice seedlings, blue light led to chlorophyll a levels similar to those of white light illuminated plants, as did with levels of Proto IX and Mg-Proto IX, while red light decreased the same precursors [ 34 ]. In the same paper, blue light upregulated the transcription of HO2 , encoding heme oxygenase and of CHLD , encoding the D subunit of Mg-chelatase, while red light increased the transcription levels of PPO1 , encoding protoporphyrin oxidase, underlining the importance of these genes in plant adaptation to altered light environments.…”