Cultivable bacteria isolated from apple trees cultivated under different crop systems: Diversity and antagonistic activity against Colletotrichum gloeosporioides

Abstract

This study evaluated the diversity of cultivable plant growth-promoting (PGP) bacteria associated with apple trees cultivated under different crop management systems and their antagonistic ability against Colletotrichum gloeosporioides. Samples of roots and rhizospheric soil from apple trees cultivated in organic and conventional orchards in southern Brazil were collected, together with soil samples from an area never used for agriculture (native field). Bacteria were identified at the genus level by PCR-RFLP and partial sequencing of the 16S rRNA, and were evaluated for some PGP abilities. The most abundant bacterial genera identified were Enterobacter (27.7%), Pseudomonas (18.7%), Burkholderia (13.7%), and Rahnella (12.3%). Sixty-nine isolates presented some antagonist activity against C. gloeosporioides. In a greenhouse experiment, five days after exposure to C. gloeosporioides, an average of 30% of the leaf area of plants inoculated with isolate 89 (identified as Burkholderia sp.) were infected, whereas 60 to 73% of the leaf area of untreated plants was affected by fungal attack. Our results allowed us to infer how anthropogenic activity is affecting the bacterial communities in soil associated with apple tree crop systems, and to obtain an isolate that was able to delay the emergence of an important disease for this culture.

Isolation, Characterization and Selection of Bacteria that Promote Plant Growth in Grapevines (Vitis sp.)

“…Such results were comparable to those obtained by Passos et al (2014) who also did not achieve any statistically significant results in terms of the root's dry mass when they inoculated apple seedlings with five bacterial isolates from the rhizosphere. Dawwam et al (2013) observed an increase in nitrogen (50.5%) and phosphorus content (48.3%) in the Ipomoea batatas L.'s dry mass when compared to the control group; increases that were also observed in this study with respect to carbon (10% to 14%) and nitrogen (61.7% to 140%) contents.…”

“…Dawwam et al (2013) observed an increase in nitrogen (50.5%) and phosphorus content (48.3%) in the Ipomoea batatas L.'s dry mass when compared to the control group; increases that were also observed in this study with respect to carbon (10% to 14%) and nitrogen (61.7% to 140%) contents. Passos et al (2014) analyzed apple seedlings in terms of absorption of nitrogen, phosphorus and potassium, and determined that only plants inoculated with Burkholderia sp. showed high levels of phosphorus absorption.…”

Root-associated bacteria promote grapevine growth: from the laboratory to the field

“…Only apple, desert legume and mango trees have been studied (Shishido 1996;Aslantas et al 2007;Bashan et al 2009;Bashan et al 2012;Jaos Frederico et al 2014). The effects of PGP bacteria on annual crops have also been the focus of research (Bashan et al 2014 and references therein).…”

Morphological identification of Ilyonectria liriodendri and its interaction with plant growth-promoting bacteria in grapevine rootstocks

“…nov. isolated POA 89 (BACH et al, 2017) exercised greater control (TABLE 1). This bacterium originates from grasslands soils from Lages (SC) and is characterized by producing siderophore, by depriving organisms of the absorption of iron, and for producing the auxin indoleacetic acid (AIA) and for not producing phosphate (PASSOS et al, 2014) as well as for having an inhibitory control on the mean mycelial growth of the phytopathogen of 42.69% (FIGURE 1D, TABLE 1). Similar inhibitory effects were obtained by Shiomi et al (2008), who observed a strong antagonistic action in vitro of Bacillus subtilis and B. lentimorbus against the fungus Rhizoctonia solani.…”