Bamboos (Bambusoideae, Poaceae) are multiple-purpose perennial grasses, which display a growing production chain in Brazil. One of the main bottlenecks is high-quality supplying of plantlets, then requiring efficient mass propagation methods, such as micropropagation. Contamination by microorganisms is recurrent in bamboo in vitro cultures, although some of those manifestations are considered endophytes harboring plant growth promotion potential. The isolation of endophytic bacteria from in vitro cultures of Dendrocalamus asper and Bambusa oldhamii was performed to assess their potential growth-promoting effect in co-cultivation with in vitro plants of Guadua chacoensis, an economically promising bamboo species. Among the total bacterial collection (32 isolates), all of them showed growth-promotion potential as indole compounds-producers. Sequences of 16S rRNA genes from eight selected isolates were newly generated, and the BLASTn similarity test recovered four bacterial genera (Bacillus, Brevibacillus, Serratia, and Atlantibacter) and six species. The co-cultivation experiment was carried out with three isolates selected based on their low- (Ba16), medium- (Ba03), and high-yield (Ba24) production of indole compounds, and Bayesian inferences strongly supported them as Bacillus subtilis, Serratia marcescens, and Brevibacillus parabrevis, respectively. The co-cultivation with three bacterial isolates, and their dilution levels, did not influence shoot or root growth and, however, did not cause apparent impairment for G. chacoensis in vitro cultures. Taken together, the isolation of endophytic microorganisms from field-growth bamboo clump and its co-cultivation with in vitro cultures of bamboos is possible, encouraging a continuous discovery and improvement of micropropagation techniques.

竹子（竹科、禾本科）是多用途多年生草本植物，在巴西显示出不断增长的生产链。主要瓶颈之一是苗木的高质量供应，然后需要有效的大规模繁殖方法，例如微繁殖。微生物污染在竹子体外培养中反复发生，尽管其中一些表现被认为是具有促进植物生长潜力的内生菌。对毛菖蒲和竹竹体外培养物中的内生细菌进行了分离，以评估它们在与瓜杜瓦 chacoensis体外植物共培养中的潜在促生长作用，一种经济上有前途的竹种。在所有细菌集合（32 个分离株）中，它们都显示出作为吲哚化合物生产者的生长促进潜力。新生成了8 个选定分离株的 16S rRNA 基因序列，BLASTn 相似性测试回收了 4 个细菌属（芽孢杆菌属、短杆菌属、沙雷氏菌属和亚特兰蒂杆菌属）和 6 个物种。根据吲哚化合物的低产（Ba16）、中产（Ba03）和高产（Ba24）选择的三个分离株进行了共培养实验，贝叶斯推断强烈支持它们为枯草芽孢杆菌、沙雷氏菌粘质，和分别为短短杆菌。与三种细菌分离物的共培养及其稀释水平不会影响芽或根的生长，但不会对G. chacoensis 体外培养造成明显损害。总之，从田间生长的竹丛中分离内生微生物并将其与竹子的体外培养共培养是可能的，这鼓励了微繁殖技术的不断发现和改进。