Dutta Swarnalee, Balaraju Kotnala, Oh Soh-Young, Lee Mi-Hyun, Lee Se Weon, Lee Yong Hwan, Park Kyungseok
Division of Biotechnology, Jeonbuk National University, Iksan-si, Republic of Korea.
Crop Protection Division, National Institute of Agricultural Sciences, Wanju-gun, Republic of Korea.
Front Microbiol. 2025 Jan 10;15:1524888. doi: 10.3389/fmicb.2024.1524888. eCollection 2024.
Volatile organic compounds (VOCs) produced by potential plant growth-promoting rhizobacteria (PGPR) play an important role in plant interactions. However, the mechanisms underlying this phenomenon are not well understood. Our findings show that the influence of VOCs from the PGPR strain (EXTN-1) on tobacco plant growth is dependent on the culture media used. The VOCs released from sugar-rich media such as potato dextrose agar (PDA) and King's B (KB) media were highly effective. However, exposure to VOCs from nutrient agar (NA), tryptic soy agar (TSA), and Luria-Bertani (LB) resulted in chlorosis and stunted plant growth. This effect was caused by the discharge of a large amount of ammonia that altered the pH of the plant growth media. Seedlings exposed to VOCs for 10 days exhibited improved growth even after the VOCs were eliminated under greenhouse conditions. Priming of seeds with VOCs for 24 and 48 h induced higher growth than the untreated control, and seeds with 48 h exposure were better as compared to 24 h treatment. Chemical characterization of VOCs emitted by EXTN-1 in different media using solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) showed the presence of 2,3-butanedione and monoxime in all spectra. However, 1-butanol was the prominent peak in VOC of EXTN-1 grown in KB and NA, while acetoin was highest in PDA, followed by KB. Heneicosane and benzaldehyde were exclusively produced in NA media, and these synthetic compounds improved growth in the I-plate assay. This work indicates that VOCs released from EXTN-1 are important for the growth-promoting effect of EXTN-1.
潜在的植物促生根际细菌（PGPR）产生的挥发性有机化合物（VOCs）在植物相互作用中发挥着重要作用。然而，这一现象背后的机制尚未得到充分理解。我们的研究结果表明，PGPR菌株（EXTN-1）产生的VOCs对烟草植株生长的影响取决于所使用的培养基。从富含糖分的培养基如马铃薯葡萄糖琼脂（PDA）和King氏B（KB）培养基中释放的VOCs具有很高的效果。然而，暴露于营养琼脂（NA）、胰蛋白胨大豆琼脂（TSA）和Luria-Bertani（LB）培养基产生的VOCs会导致叶片黄化和植株生长受阻。这种影响是由大量氨气的排放导致植物生长培养基的pH值改变引起的。在温室条件下，即使VOCs被去除，暴露于VOCs 10天的幼苗仍表现出更好的生长。用VOCs对种子进行24小时和48小时的引发处理比未处理的对照诱导出更高的生长，并且与24小时处理相比，48小时暴露的种子效果更好。使用固相微萃取（SPME）结合气相色谱-质谱联用（GC-MS）对EXTN-1在不同培养基中排放的VOCs进行化学表征，结果显示在所有光谱中均存在2,3-丁二酮和单肟。然而，1-丁醇是在KB和NA培养基中生长的EXTN-1的VOC中的主峰，而乙偶姻在PDA中含量最高，其次是KB。二十一烷和苯甲醛仅在NA培养基中产生，并且这些合成化合物在平板试验中促进了生长。这项工作表明，EXTN-1释放的VOCs对EXTN-1的促生长作用很重要。
