The percentage of germination and the vigor of seeds are major determinants for an efficient seedling production to successfully establishment a crop. Some Capsicum annuum germinate within a few days, but others take until 21 days. Pepper seeds have significant amounts of free and bound polyphenols that are modified during the germination process. Phenolic compounds are used by seed to scavenge free radicals, they can also work as signal compounds or they can be related to plant's defense participating in the induced systemic resistance (ISR). However, the effect of plant growth-promoting rhizobacteria (PGPR) on pepper seed germination and the changes on phenolic profile has not been examined. In this study, we evaluated the transformation of phenolic compounds during seed germination produced by the inoculation with native PGPR on pepper seeds germination. Five bacterial strains: Cellulosimicrobium 60I1, Ochrobactrum 53F, Enterobacter 64S1, Pseudomonas 42P4 and Azospirillum brasilense Az39 were investigated. Our results showed that seed inoculation enhanced significantly seed germination, seedling growth, root length, and diameter of pepper seedling. In addition, changes in the profile of free and bound phenolic compounds were observed in seeds inoculated with PGPR. The free phenolic compounds were higher in the seedling inoculated with 60I1, 42P4 or the consortium with respect to control. The phenolic acid increased in seed inoculated suggests an elicitation of phenylpropanoid pathway related to ISR. The free flavonoids, naringenin, and rutin were present in the control treatment, while they were not detectable in the inoculated treatments. These could be used as a carbon source by PGPR during the germination or converted into flavonols that could protect the plants under abiotic stress. The tyrosol was present in 60I1 and in 60I1+42P4 treatment. The most effective strains were Cellulosimicrobium 60I1 and Pseudomonas 42P4 that increased their potential when it was used together.

发芽率和种子活力是成功生产农作物的有效苗木生产的主要决定因素。一些辣椒在几天之内发芽，而其他的则要等到21天。胡椒种子具有大量的游离和结合多酚，它们在发芽过程中会发生修饰。种子使用酚类化合物清除自由基，它们也可以作为信号化合物起作用，或者与参与诱导的系统抗性（ISR）的植物防御有关。但是，尚未研究促进植物生长的根际细菌（PGPR）对辣椒种子发芽的影响以及酚类成分的变化。在这项研究中，我们评估了天然PGPR接种辣椒种子发芽后种子发芽过程中酚类化合物的转化过程。五种细菌菌株：纤维素酶60I1，，骨53F，肠杆菌64S1，假单胞菌42P4和巴西固氮螺菌对Az39进行了调查。我们的结果表明，接种种子可以显着增强辣椒种子的萌发，幼苗生长，根长和直径。另外，在接种PGPR的种子中观察到游离和结合的酚类化合物的特征发生变化。相对于对照，接种60I1、42P4或财团的幼苗中的游离酚类化合物含量较高。接种的种子中酚酸含量的增加暗示了与ISR相关的苯丙烷途径的诱导。对照处理中存在游离类黄酮，柚皮素和芦丁，而在接种处理中未检出它们。这些可以在发芽过程中用作PGPR的碳源，或转化为可在非生物胁迫下保护植物的黄酮醇。酪醇存在于60I1和60I1 + 42P4处理中。最有效的菌株是纤维素酶60I1和假单胞菌42P4一起使用时增加了它们的潜力。