Soil Study

Dramatically Dynamic Genomic Evolution of a Mighty Mite As a major natural enemy of several damaging agricultural pests, the predatory mite Metaseiulus occidentalis is used in many agricultural settings as an effective biological control agent. Some of its favorite prey include spider mites that feed on and destroy various fruits including strawberries, apples, peaches and grapes. "I have been studying the behavior, ecology, and molecular biology of these mites for more than 40 years," said Prof. Marjorie Hoy lead author from the University of Florida USA, "so I was very keen to sequence the entire genome to reveal the full catalogue of genes." To explore the unique biology of this agriculturally important predator the researchers focused their studies on genes putatively involved in processes linked to paralysis and pre-oral digestion of prey species and its rather rare par haploid sex determination system, as well as how it senses chemical cues from its surro

Modern Corn Hybrids More Resilient to Nitrogen Stress In an analysis of 86 field experiments, agronomists found that corn hybrids released after 1990 prove more resilient than their predecessors in multiple ways. Modern hybrids maintain per-plant yield in environments with low nitrogen, can bounce back from mid-season stress and have an improved ability to take up nitrogen after silking, even if they suffered from nitrogen deficiency during flowering. The study suggests reserving a portion of nitrogen fertilizer to apply later in the season could be a good bet for growers, said Tony Vyn, professor of agronomy. "This is like insurance," he said. "Previously, withholding some of your nitrogen for later could be perceived as a risky venture -- you don't want to inadvertently cause nitrogen deficiency. But this paper suggests that with modern hybrids, that risk is lower." Nitrogen is an essential building block of plant proteins and plays a vital role

The Fight Against Citrus Greening Disease A new study of the citrus greening bacterium's effects on its insect vector, the Asian citrus psyllid, reveals multiple changes within the insect. During the infection, the pathogen affects the 'good' bacteria living inside the insect and alters the psyllid's metabolism in ways that could help spread the pathogen further. Ultimately, the study may reveal weak points in the transmission cycle that could yield novel and highly specific targets for control strategies. These approaches could be more effective and environmentally friendly than large-scale pesticide use. The study appears in the journal PLOS ONE. "Our work in this area could not be timelier," said Michelle Cilia, an assistant professor at BTI and research molecular biologist in the U.S. Department of Agriculture's Agricultural Research Service. "Last week, the USDA's National Agricultural Statistics Service lowered its already dire pr

Genome-Edited Plants, Without DNA What makes this work so groundbreaking is that these genetic modifications look just like genetic variations resulting from the selective breeding that farmers have been doing for millennia. IBS Director of the Center for Genome Engineering Jin-Soo Kim explains that "the targeted sites contained germ line-transmissible small insertions or deletions that are indistinguishable from naturally occurring genetic variation." CRISPR is an acronym for Clustered Regularly Interspaced Short Palindromic Repeat, which refers to the unique repeated DNA sequences found in bacteria and archaea. CRISPR is now used widely for genome editing. What's crucial in genetic engineering is for the gene editing tool to be accurate and precise, which is where CRISPR-Cas9 excels. CRISPR-Cas9 uses a single guide RNA (sgRNA) to identify and edit the target gene and Cas9 (a protein) then cleaves the gene, resulting in site-specific DNA double-strand breaks (

Increasing Production of Seed Oils Many plants store oil and protein in their seeds as energy sources needed for germination. The National Institute for Basic Biology's Drs. Masatake Kanai, Shoji Mano and Mikio Nishimura et al., in the process of studying the mechanism that controls the synthesis and degradation of oils in plant seeds, revealed that oils are actively synthesized only during the mid-phase of the seed formation process. The research group considered that by extending the period seeds synthesize oils, they should be able to increase their oil content in seeds. Therefore, using the model plant Arabidopsis, they extended the expression time of WRI1, a gene that activates oil synthesis. As a result, they were able to increase the oil content of the seeds to 140% as compared to wild-type. Also, while extending the oil synthesis phase, suppressing protein synthesis in the late-phase of seed formation increased the oil content of the seeds as compared to wild-typ

Genetic Transfer to Prevent Self-Pollination Self-pollination or 'selfing' can be bad for a plant resulting in inbreeding and less healthy offspring. This breakthrough could be used to breed stronger more resilient crops faster and at lower cost; a new approach in the quest for a secure and plentiful food supply. The team took the self-fertile plant thale cress -- Arabidopsis thaliana -- a relative of cabbages, cauliflowers and oilseed rape, and made it self-incompatible by the transfer of just two genes from poppies that enable the recipient plant to recognize and reject its own pollen whilst permitting cross-pollination. Such conversion of a selfing plant to a self-incompatible one has been a long term goal of self-incompatibility research. The basic anatomy of most flowers means the male pollen is produced next to the female reproductive organs running the real risk of self-pollination, rather than receiving pollen from a different flower transported by the wind