Differential Rhizosphere Establishment and Cyanide Production by Alginate-Formulated Weed-Deleterious Rhizobacteria

Bioassays using cell cultures and callus tissues of leafy spurge were devised to evaluate the potential of rhizobacteria as biocontrol agents. Rhizobacteria isolated from roots of leafy spurge seedlings were screened in suspension-cultured leafy spurge cells. Cell viability was assessed using the Evan's blue bioassay 48 h after bacterial inoculation. Among the 30 isolates tested, LS102 and LS105 consistently caused intensive cell death determined by measuring the A630of the inoculated cell cultures. Cell death was 2.5 to 3 times higher in cultures inoculated with LS105 and LS102, respectively, than in the control. Population levels of the two isolates within cell cultures and callus tissues of leafy spurge increased during the first 48 h. Leafy spurge callus tissues were inoculated with rhizobacteria either directly or by using the Host Pathogen Interaction System (HPIS). The latter exposes calli to bacteria without any physical contact. LS102 caused cellular leakage and eventually death of the callus tissue. Callus growth was reduced by about 30 to 70% when exposed to LS102 and LS105, respectively. Results suggest that these two isolates may affect leafy spurge at the cellular level by different mechanisms. A screening method based on cell cultures and callus tissues offers a good and rapid technique for detecting deleterious rhizobacteria with potential as biocontrol agents for leafy spurge.

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Pemanfaatan Deleterious rhizobacteria Untuk Mengendalikan Gulma Utama Tanaman Padi di Kabupaten Jember

Jurnal Pengendalian Hayati ◽

10.19184/jph.v2i2.17139 ◽

2019 ◽

Vol 2 (2) ◽

pp. 40

Author(s):

Yogi Ardhi Cahyadi ◽

Saifuddin Hasjim

Keyword(s):

Biological Control ◽

Plant Pathogens ◽

Plant Protection ◽

Sampling Technique ◽

Spherical Shape ◽

Edge Type ◽

Randomized Sampling ◽

Rice Plants ◽

Deleterious Rhizobacteria

The purpose of the study was to determine the characteristics of plant pathogens from Deleterious rhizobacteria (DRB) that have the potential as biological control agents in the main weeds of rice plants. This research was conducted in April-August 2019 at the Plant Protection Laboratory, Faculty of Agriculture, University of Jember. Rhizobacteria sampling was taken from rice fields in Mayang District. Weed sampling technique is done by purposive randomized sampling. The collections of pathogen-infected weeds are then isolated using laminar airflow and identified through several test stages. DRB exploration results obtained by two microorganisms that can be used as biological control to control the main weeds of rice plants from the Pseudomonas group, they are P. syringae pv. glycinea (M1) and P. syringae pv. syringae (M2). Based on the identification of the two isolates morphologically that (M1) has a greenish-white color with a flat edge type. Whereas the isolate code (M2) has a yellowish murky white color with a rather irregular jagged edge type. However, the two isolates have similarities in spherical shape. The physiological observations of both M1 and M2 isolate from the Catalase test, fluorescent pigments produce gram-positive (+) while gram tests produce gram-negative (-). The conclusion of this research is the characterization of P. syringae pv. glycinea (M1) and P. syringae pv. syringae (M2) both morphologically and physiologically.

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Growth response of weed and crop seedlings to deleterious rhizobacteria

Biological Control ◽

10.1016/j.biocontrol.2006.04.016 ◽

2006 ◽

Vol 39 (1) ◽

pp. 58-65 ◽

Cited By ~ 25

Author(s):

Jianmei Li ◽

Robert J. Kremer

Keyword(s):

Growth Response ◽

Deleterious Rhizobacteria

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Influence of Deleterious Rhizobacteria on Leafy Spurge (Euphorbia esula) Roots

Weed Technology ◽

10.1017/s0890037x00042317 ◽

1999 ◽

Vol 13 (4) ◽

pp. 835-839 ◽

Cited By ~ 11

Author(s):

Mark A. Brinkman ◽

Sharon A. Clay ◽

Robert J. Kremer

Keyword(s):

South Dakota ◽

Leafy Spurge ◽

Carbohydrate Content ◽

Root Weight ◽

Starch Granules ◽

Bacterial Strains ◽

North Central ◽

Deleterious Rhizobacteria ◽

Colony Forming Units ◽

Central South

Rhizobacteria have been shown to be phytotoxic to leafy spurge in laboratory assays. This field study investigated the influence of two strains ofPseudomonas fluorescens[Trevisan, (Migula)], deleterious rhizobacteria (DRB), on root weight, root bud number, and root carbohydrate content of leafy spurge at three sites located in northeast and north-central South Dakota. Soils were inoculated with 2 g of starch-based granules containing no bacteria or starch granules containing 108colony-forming units (cfu)/g of either bacterial strain LS102 (Montana origin) or LS174 (South Dakota origin). Bacterial strains were detected on root samples from treated areas. Root weight and root carbohydrate content were reduced about 20% compared to roots from control plots.

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