Scholarlink

<p>Leaf spot and blight caused by <i>Alternaria</i> spp. severely constrain propagation of <i>Dracaena hanningtonii</i>, <i>Dracaena serrulata</i> and <i>Kleinia odora</i> at Oman Botanic Garden, Muscat, Sultanate of Oman. Because the disease reduces nursery quality and limits conservation-oriented propagation, this study screened phyllosphere-associated antagonistic bacteria under controlled experimental conditions. Forty-nine bacterial isolates from asymptomatic leaves or phylloclades were screened against seven pathogenic <i>Alternaria</i> isolates. Ten showed preliminary antagonism; <i>Serratia marcescens</i> D11 was the most consistent, inhibiting mycelial growth by 44.2–52.3% in dual culture. Scanning electron microscopy showed wrinkling, perforation and collapse of treated hyphae. <i>Serratia marcescens</i> D11 formed biofilms and produced a prodigiosin-like red pigment, cellulase, β-glucanase, amylase, protease, lipase and catalase. Headspace-SPME-GC-MS indicated that the <i>S. marcescens</i> D11 volatile profile was dominated by a compound tentatively identified as dimethyl disulfide (82.86% relative peak area). <i>Serratia marcescens</i> D11 VOCs reduced mycelial growth by 28.6–57.7%. In controlled greenhouse assays using artificial wounding followed by mycelial-plug inoculation, a single foliar application of <i>S. marcescens</i> D11 24&#xa0;h before inoculation reduced lesion area by 71.1–92.9%. It was more effective than copper oxychloride and was statistically comparable to difenoconazole under the tested conditions. These findings identify <i>S. marcescens</i> D11 as a promising preliminary antagonist under the experimental conditions used. However, because <i>S. marcescens</i> can include opportunistic human pathogenic strains, strain D11 cannot be recommended for practical application until a comprehensive biosafety evaluation, including whole-genome analysis, screening for virulence and antimicrobial-resistance genes, and appropriate phenotypic safety assays, has been completed.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Phyllosphere-derived Serratia marcescens D11 suppresses Alternaria leaf spot and blight in Dracaena and Kleinia species under controlled greenhouse conditions

  • 期刊论文

  • 发表日期：

    2026年7月27日

查看全文
  • Thamodini Karunasinghe,
  • Rethinasamy Velazhahan,
  • Shah Hussain,
  • Abdullah Mohammed Al-Sadi

摘要

Leaf spot and blight caused by Alternaria spp. severely constrain propagation of Dracaena hanningtonii, Dracaena serrulata and Kleinia odora at Oman Botanic Garden, Muscat, Sultanate of Oman. Because the disease reduces nursery quality and limits conservation-oriented propagation, this study screened phyllosphere-associated antagonistic bacteria under controlled experimental conditions. Forty-nine bacterial isolates from asymptomatic leaves or phylloclades were screened against seven pathogenic Alternaria isolates. Ten showed preliminary antagonism; Serratia marcescens D11 was the most consistent, inhibiting mycelial growth by 44.2–52.3% in dual culture. Scanning electron microscopy showed wrinkling, perforation and collapse of treated hyphae. Serratia marcescens D11 formed biofilms and produced a prodigiosin-like red pigment, cellulase, β-glucanase, amylase, protease, lipase and catalase. Headspace-SPME-GC-MS indicated that the S. marcescens D11 volatile profile was dominated by a compound tentatively identified as dimethyl disulfide (82.86% relative peak area). Serratia marcescens D11 VOCs reduced mycelial growth by 28.6–57.7%. In controlled greenhouse assays using artificial wounding followed by mycelial-plug inoculation, a single foliar application of S. marcescens D11 24 h before inoculation reduced lesion area by 71.1–92.9%. It was more effective than copper oxychloride and was statistically comparable to difenoconazole under the tested conditions. These findings identify S. marcescens D11 as a promising preliminary antagonist under the experimental conditions used. However, because S. marcescens can include opportunistic human pathogenic strains, strain D11 cannot be recommended for practical application until a comprehensive biosafety evaluation, including whole-genome analysis, screening for virulence and antimicrobial-resistance genes, and appropriate phenotypic safety assays, has been completed.