UVB Irradiation-Induced Transcriptional Changes in Lignin- and Flavonoid Biosynthesis and Indole/Tryptophan-Auxin-Responsive Genes in Rice Seedlings

Global warming accelerates the destruction of the ozone layer, increasing the amount of UVB reaching the Earth’s surface, which in turn alters plant growth and development. The effects of UVB-induced alterations of plant secondary and cell wall metabolism were previously documented; however, there i...

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Main Authors: Ga-Eun Kim, Me-Sun Kim, Jwakyung Sung
Format: Article
Language:English
Published: MDPI AG 2022-06-01
Series:Plants
Subjects:
Online Access:https://www.mdpi.com/2223-7747/11/12/1618
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author Ga-Eun Kim
Me-Sun Kim
Jwakyung Sung
author_facet Ga-Eun Kim
Me-Sun Kim
Jwakyung Sung
author_sort Ga-Eun Kim
collection DOAJ
description Global warming accelerates the destruction of the ozone layer, increasing the amount of UVB reaching the Earth’s surface, which in turn alters plant growth and development. The effects of UVB-induced alterations of plant secondary and cell wall metabolism were previously documented; however, there is little knowledge of its effects on rice seedlings during the developmental phase of leaves. In this study, we examined secondary metabolic responses to UVB stress using a transcriptomic approach, focusing on the biosynthetic pathways for lignin, flavonoid, and indole/tryptophan-auxin responses. As new leaves emerged, they were irradiated with UVB for 5 days (for 3 h/day<sup>−1</sup>). The genes encoding the enzymes related to lignin (4CL, CAD, and POD) and flavonoid biosynthesis (CHS, CHI, and FLS) were highly expressed on day 1 (younger leaves) and day 5 (older leaves) after UVB irradiation. The expression of the genes encoding the enzymes related to tryptophan biosynthesis (AS, PRT, PRAI, IGPS, and TS) increased on day 3 of UVB irradiation, and the level of tryptophan increased and showed the same temporal pattern of occurrence as the expression of the cognate gene. Interestingly, the genes encoding BBX4 and BBX11, negative regulators of UVB signaling, and SAUR27 and SAUR55, auxin response enzymes, were downregulated on day 3 of UVB irradiation. When these results are taken together, they suggest that secondary metabolic pathways in rice seedlings are influenced by the interaction between UVB irradiation and the leaf developmental stage. Thus, the strategies of protection against, adaptation to, and mitigation of UVB might be delicately regulated, and, in this context, our data provide valuable information to understand UVB-induced secondary metabolism in rice seedlings.
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spelling doaj.art-68a71be5a82044aa92503f54548b9ab12023-11-23T18:35:29ZengMDPI AGPlants2223-77472022-06-011112161810.3390/plants11121618UVB Irradiation-Induced Transcriptional Changes in Lignin- and Flavonoid Biosynthesis and Indole/Tryptophan-Auxin-Responsive Genes in Rice SeedlingsGa-Eun Kim0Me-Sun Kim1Jwakyung Sung2Department of Crop Science, Chungbuk National University, Cheongju 28644, KoreaDepartment of Crop Science, Chungbuk National University, Cheongju 28644, KoreaDepartment of Crop Science, Chungbuk National University, Cheongju 28644, KoreaGlobal warming accelerates the destruction of the ozone layer, increasing the amount of UVB reaching the Earth’s surface, which in turn alters plant growth and development. The effects of UVB-induced alterations of plant secondary and cell wall metabolism were previously documented; however, there is little knowledge of its effects on rice seedlings during the developmental phase of leaves. In this study, we examined secondary metabolic responses to UVB stress using a transcriptomic approach, focusing on the biosynthetic pathways for lignin, flavonoid, and indole/tryptophan-auxin responses. As new leaves emerged, they were irradiated with UVB for 5 days (for 3 h/day<sup>−1</sup>). The genes encoding the enzymes related to lignin (4CL, CAD, and POD) and flavonoid biosynthesis (CHS, CHI, and FLS) were highly expressed on day 1 (younger leaves) and day 5 (older leaves) after UVB irradiation. The expression of the genes encoding the enzymes related to tryptophan biosynthesis (AS, PRT, PRAI, IGPS, and TS) increased on day 3 of UVB irradiation, and the level of tryptophan increased and showed the same temporal pattern of occurrence as the expression of the cognate gene. Interestingly, the genes encoding BBX4 and BBX11, negative regulators of UVB signaling, and SAUR27 and SAUR55, auxin response enzymes, were downregulated on day 3 of UVB irradiation. When these results are taken together, they suggest that secondary metabolic pathways in rice seedlings are influenced by the interaction between UVB irradiation and the leaf developmental stage. Thus, the strategies of protection against, adaptation to, and mitigation of UVB might be delicately regulated, and, in this context, our data provide valuable information to understand UVB-induced secondary metabolism in rice seedlings.https://www.mdpi.com/2223-7747/11/12/1618riceUVBligninflavonoidindole/tryptophanauxin
spellingShingle Ga-Eun Kim
Me-Sun Kim
Jwakyung Sung
UVB Irradiation-Induced Transcriptional Changes in Lignin- and Flavonoid Biosynthesis and Indole/Tryptophan-Auxin-Responsive Genes in Rice Seedlings
Plants
rice
UVB
lignin
flavonoid
indole/tryptophan
auxin
title UVB Irradiation-Induced Transcriptional Changes in Lignin- and Flavonoid Biosynthesis and Indole/Tryptophan-Auxin-Responsive Genes in Rice Seedlings
title_full UVB Irradiation-Induced Transcriptional Changes in Lignin- and Flavonoid Biosynthesis and Indole/Tryptophan-Auxin-Responsive Genes in Rice Seedlings
title_fullStr UVB Irradiation-Induced Transcriptional Changes in Lignin- and Flavonoid Biosynthesis and Indole/Tryptophan-Auxin-Responsive Genes in Rice Seedlings
title_full_unstemmed UVB Irradiation-Induced Transcriptional Changes in Lignin- and Flavonoid Biosynthesis and Indole/Tryptophan-Auxin-Responsive Genes in Rice Seedlings
title_short UVB Irradiation-Induced Transcriptional Changes in Lignin- and Flavonoid Biosynthesis and Indole/Tryptophan-Auxin-Responsive Genes in Rice Seedlings
title_sort uvb irradiation induced transcriptional changes in lignin and flavonoid biosynthesis and indole tryptophan auxin responsive genes in rice seedlings
topic rice
UVB
lignin
flavonoid
indole/tryptophan
auxin
url https://www.mdpi.com/2223-7747/11/12/1618
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AT mesunkim uvbirradiationinducedtranscriptionalchangesinligninandflavonoidbiosynthesisandindoletryptophanauxinresponsivegenesinriceseedlings
AT jwakyungsung uvbirradiationinducedtranscriptionalchangesinligninandflavonoidbiosynthesisandindoletryptophanauxinresponsivegenesinriceseedlings