López-Villamor Adrián, Nunes da Silva Marta, Vasconcelos Marta W
Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina-Laboratório Associado, Escola Superior de Biotecnologia, Rua de Diogo Botelho 1327, 4169-005 Porto, Portugal.
Misión Biológica de Galicia (CSIC), Grupo de Genética y Ecología Forestal, Apdo. 28, 36080 Pontevedra, Spain.
Tree Physiol. 2022 Dec 12;42(12):2596-2613. doi: 10.1093/treephys/tpac088.
Treatment with plant elicitors can be a promising method to induce Pinus pinaster tolerance against the pinewood nematode (PWN), Bursaphelenchus xylophilus, by promoting plant antioxidant system, micronutrient accumulation and by modulating plant-associated bacterial populations. To test this hypothesis, plants were sprayed with methyl jasmonate (MeJA), salicylic acid (SA) or benzo (1,2,3)-thiadiazole-7-carbothioic acid-S-methyl ester (BTH), and evaluated until 35 days after-inoculation (dai) for: i) extent of foliar symptoms; ii) nematode density inside stem tissues; iii) proxies for oxidative damage and antioxidant activity, iv) micronutrient concentration and v) bacterial diversity. Compared with non-elicited plants, plant elicitation, particularly with BTH, significantly decreased nematodes density inside stem tissues (by 0.63-fold). Concordantly, without elicitation plant mortality reached 12.5% while no mortality was observed in elicited plants. BTH-elicited plants had significantly higher concentrations of anthocyanins and carotenoids at the end of the assay than SA-elicited and MeJA-elicited plants, which possibly contributed to the lower PWN colonization and degree of foliar symptoms observed. Accordingly, MeJA and SA led to increased lipid peroxidation at 28 dai (by 2.64- and 2.52-fold, respectively) in comparison with BTH (by 1.10-fold), corroborating its higher potential in increasing plant antioxidative response during infection. Moreover, carotenoids showed a negative correlation with nematode migration, whereas polyphenols showed a positive correlation. Elicitors also induced changes in the bacterial community of infected P. pinaster plants, increasing the diversity of specific populations. Finally, elicitors induced significant changes in micronutrients accumulation in plant tissues, namely a decrease in the concentration of B, Mn and Ni in plants treated with BTH compared to those treated with the other elicitors. Altogether, results suggest that elicitation with MeJA, SA and, particularly, BTH, increases tolerance against B. xylophilus by promoting plant antioxidant system, changing the accumulation of essential micronutrients and modulating plant-associated bacterial diversity.
通过促进植物抗氧化系统、微量营养素积累以及调节植物相关细菌种群，用植物激发子处理可能是诱导海岸松对松材线虫（PWN），即松材线虫（Bursaphelenchus xylophilus）产生耐受性的一种有前景的方法。为了验证这一假设，对植物喷洒茉莉酸甲酯（MeJA）、水杨酸（SA）或苯并（1,2,3）-噻二唑-7-硫代羧酸-S-甲酯（BTH），并在接种后35天（dai）内进行评估，评估内容包括：i）叶部症状的程度；ii）茎组织内线虫密度；iii）氧化损伤和抗氧化活性的指标；iv）微量营养素浓度；v）细菌多样性。与未用激发子处理的植物相比，植物激发处理，尤其是用BTH处理，显著降低了茎组织内线虫密度（降低了0.63倍）。相应地，未用激发子处理的植物死亡率达到12.5%，而用激发子处理的植物未观察到死亡。在试验结束时，BTH处理的植物中花青素和类胡萝卜素的浓度显著高于SA处理和MeJA处理的植物，这可能是导致观察到的较低的松材线虫定殖率和叶部症状程度的原因。因此，与BTH处理（增加了1.10倍）相比，MeJA和SA在接种后28天导致脂质过氧化增加（分别增加了2.64倍和2.52倍），证实了其在感染期间增强植物抗氧化反应的更高潜力。此外，类胡萝卜素与线虫迁移呈负相关 , 而多酚呈正相关。激发子还诱导了受感染的海岸松植物细菌群落的变化，增加了特定种群的多样性。最后，激发子诱导了植物组织中微量营养素积累的显著变化，即与用其他激发子处理的植物相比，用BTH处理的植物中硼、锰和镍的浓度降低。总之，结果表明，用MeJA、SA，特别是BTH进行激发处理，通过促进植物抗氧化系统、改变必需微量营养素的积累以及调节植物相关细菌多样性，提高了对松材线虫的耐受性。
