Microorganisms, also called as microbes, live in every part of the biosphere, including soil, water, and air. Plant pathogens are the microbes that infect plants and cause diseases. In history, some plant diseases led to tremendous negative impacts on society. In 1845, potato blight disease was prevalent in all potato growing regions in Ireland. Phytophthora infestans, a fungus, was responsible for the disease which ultimately caused the Irish Potato Famine resulting in a million Irish deaths. Ever since, more attentions were made to study plant pathogens. Generally speaking, there are four main types of plant pathogens: bacteria, fungi, nematodes and viruses. Some common pathogenic bacteria for plants are: Pseudomonas which is responsible for tomato wilt, Erwinia for corn Stewart’s disease (wilt), and Xanthomonas for citrus canker; some common pathogenic fungi are: Fusarium which is responsible for root rot diseases of soybeans and corn, Sclerotinia for wheat wilt, Ustilago for corn smut; one common pathogenic nematode is Root-knot nematode (Meloidogyne) which is responsible for root-knot diseases of major crops, such as corn, soybeans, and cotton. In addition, some viruses (e.g. Tomato spotted wilt virus) were known to infect plants as well. As different plant pathogens can target a different groups of plants (i.e. host range), accurate diagnostics of plant pathogens is needed to help farmers to identify effective control measures to control diseases. Let’s look at one scenario, if a pathogen is identified as Sclerotium rolfsii Sacc, a fungal pathogen that is known to be able to infect both corn and wheat plants causing a Southern Blight Disease, then the same control measures can be applied to control this disease on both corn and wheat plants. Furthermore, routine inspections for pathogens on soil in the field or seeds to be planted need to be done to prevent diseases caused by soil-borne or seed-borne pathogens. One of the important soil-borne pathogens is Root Knot Nematode, and one of the important seedborne pathogens is Xanthomonas campestris, a bacterial pathogen, which cause black rot of crucifers plants (e.g. most common vegetables). At MIL, with expertise in plant pathology, we can identify plant pathogens in a timely fashion and perform further investigations on plant pathogens if needed. Our work will enable our customers to make precise decisions on disease management.
Microbes for phytoremediation
In nature, some microbes interact with plants to create a sustainable environment by stabilizing or reducing contamination through a process called phytoremediation. These microbes living at plant roots, e.g. soil microbes, can break down the soil contaminants to less harmful chemicals. As a result, plants can survive in contaminated soils. Recently phytoremediation has played an important part in agriculture and has become one of the important tools for creating sustainable environments. In the early 1980’s, researchers began to scrutinize the work of other pioneering phytoremediation technology. After the nuclear accident at Chernobyl, Ukraine, in 1986 Phytotech began using plants to decontaminate water and soil. This was to be the proving ground for the new technology. In addition, some plant growth-promoting bacteria associated with plant roots also may exert some beneficial effects on plant growth and nutrition through a number of mechanisms such as N2 fixation, production of phytohormones and siderophores, and transformation of nutrient elements when they are either applied to seeds or incorporated into the soil. The use of rhizobacteria in combination with plants is expected to provide high efficiency for phytoremediation. Therefore, the mechanism of rhizobacteria to enhance phytoremediation received some attention. At MIL, we worked with our clients to identify bacteria with potentials in phytoremediation and will continue the investigations with our customers to identify effective solutions to build a sustainable environment
In modern agriculture, many chemicals, or pesticides, have been developed to control plant diseases and pests. As crops grow in the field, some unwanted weeds may also grow along with crops for the competition of nutrients in soil. As a result, the crop yield may be reduced due to the growth of unwanted weeds. Herbicide was then invented to kill the unwanted weeds in the field. One of the popular herbicides is Roundup with glyphosate as the major ingredient. Glyphosate was reported to have low toxicity to animal life compared with other herbicides while it also has broad spectrum. With the increased use of Roundup, some people started to worry about its potential effects in environment. At MIL, we are certified to test glyphosate in various types of samples provided from our customers.