Background <p>Oat (<i>Avena sativa</i> L.), a key forage crop, is highly susceptible to water deficit. Many studies have elucidated the mechanisms through which oat leaves respond to drought; however, little is known about these mechanisms in roots.</p> Results <p>We compared the physiological, transcriptomic, and metabolomic responses of a drought-tolerant oat cultivar (DA92-2F6, D) and a drought-sensitive cultivar (Longyan No.3, L3) at 0, 6, 24, and 72&#xa0;h under PEG-induced drought stress. We found that drought stress caused significant increases in malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) levels, with the most pronounced accumulation observed in L3. D varieties maintained significantly higher antioxidant enzyme activities (CAT, POD, SOD, APX; <i>P &lt;</i> 0.05), which causes variations in drought resistance. Additionally, differences in gene expression and drought-resistance pathways between the two varieties were clarified using transcriptome analysis. Through a multi-omics joint analysis, flavonoid biosynthesis and plant hormone signals were identified as the core drought resistance pathways in oat roots. Candidate genes associated with drought response included <i>CHS</i>,<i> C4H</i>,<i> SHT</i>,<i> CYP98A3</i>,<i> FLS</i>, and <i>CHIL</i> (flavonoid biosynthesis); and <i>AUX/IAA</i>,<i> GH3</i>,<i> B-ARR</i>,<i> DELLA</i>,<i> PP2C</i>,<i> SnRK2</i>,<i> JAZ</i>,<i> MYC2</i>,<i> CPK</i>, and <i>GS2</i> (hormone signaling). Candidate indicator metabolites (phlorizin, naringenin, sakuranetin, pinobanksin) affecting drought resistance were identified. In addition, exogenous phlorizin effectively enhanced the drought response of the sensitive genotype L3.</p> Conclusions <p>This study provides useful data for investigating drought responses in plant root and offers theoretical support for plant breeding for drought resistance.</p>

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Molecular mechanism of drought resistance in oat roots revealed using integrated physiological and multi-omics analyses

  • Panpan Huang,
  • Jikuan Chai,
  • Kuiju Niu,
  • Liang Zeng,
  • Wenping Wang,
  • Yanming Ma,
  • Yanan Cao,
  • Guiqin Zhao

摘要

Background

Oat (Avena sativa L.), a key forage crop, is highly susceptible to water deficit. Many studies have elucidated the mechanisms through which oat leaves respond to drought; however, little is known about these mechanisms in roots.

Results

We compared the physiological, transcriptomic, and metabolomic responses of a drought-tolerant oat cultivar (DA92-2F6, D) and a drought-sensitive cultivar (Longyan No.3, L3) at 0, 6, 24, and 72 h under PEG-induced drought stress. We found that drought stress caused significant increases in malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) levels, with the most pronounced accumulation observed in L3. D varieties maintained significantly higher antioxidant enzyme activities (CAT, POD, SOD, APX; P < 0.05), which causes variations in drought resistance. Additionally, differences in gene expression and drought-resistance pathways between the two varieties were clarified using transcriptome analysis. Through a multi-omics joint analysis, flavonoid biosynthesis and plant hormone signals were identified as the core drought resistance pathways in oat roots. Candidate genes associated with drought response included CHS, C4H, SHT, CYP98A3, FLS, and CHIL (flavonoid biosynthesis); and AUX/IAA, GH3, B-ARR, DELLA, PP2C, SnRK2, JAZ, MYC2, CPK, and GS2 (hormone signaling). Candidate indicator metabolites (phlorizin, naringenin, sakuranetin, pinobanksin) affecting drought resistance were identified. In addition, exogenous phlorizin effectively enhanced the drought response of the sensitive genotype L3.

Conclusions

This study provides useful data for investigating drought responses in plant root and offers theoretical support for plant breeding for drought resistance.