The Classification of Duckweed and Its Bacterial Community: A Review

Duckweed is the world underutilized tiniest aquatic plant which full of benefit especially as animal feed other than human consumption. However, usage of duckweed as food requires more understanding especially on its safety. This review paper describes classification of duckweed and bacteria diversity in duckweed plant which associated with various types of bacteria includes endophytic and epiphytic bacteria involving plant and human pathogen. Duckweed taxonomy can be divided into five genera according to their characteristics which are genera Spirodela and Landoltia, genus Lemna, genus Wolffiella, and genus Wolffia. Endophytic bacteria in duckweed plays a beneficial role which can help to improve the growth of duckweed such as Paenibacillus lemnae giving a high adhering ability in plant by promoting the growth of plant. Janibacter spp. is one of endophytic bacteria which can help the plant by increase plant nutrient absorption, Deinococcus spp. act as protector of a plant from pathogenic bacteria, and Acinetobacter spp. have potential to acquire anti-microbial by producing enzymes β-lactamases to protect the plant from disease. However, some bacteria presence in duckweed such as plant pathogen and epiphytic bacteria can cause disease in the plant includes Pseudomonas syringae and Xanthomonas spp. which can create bacterial canker on the leaf of the plant, and Erwinia spp. can cause fire blight. Since duckweed can also consumed in raw state, human pathogen bacteria presence in the plant which can lead to foodborne illness is also discussed in this paper. Source of bacterial contamination of duckweed plant is also reviewed. Water irrigation and improper handling and hygiene are sources contamination of bacterial transmitted into duckweed. Bacteria able to colonize duckweed through multiple mechanisms. Transmission bacteria into duckweed plant host through stomata which were aid by insects are called indirect contact and manyother modes of transmission are also highlighted. Generally, duckweed can be divided into five genera and inhibited by various pathogen and non-pathogenic bacteria introduced naturally or through contamination