Chemical Ecology – Page 5

Listening in on someone else’s conversation

September 15, 2018September 22, 2018Bhodi Tims

This paper in Science, investigated molecular conversation between a parasitic plant, dodder (C. pentagona), and two host plants, by sequencing all three transcriptomes.

Genes, defined segments of DNA (deoxyribonucleic acid), must be “read” and copied (transcribed) into RNA (ribonucleic acid). These gene readouts are called transcripts, and a transcriptome is a collection of all the gene readouts present in a cell, The major type, of gene readout is called messenger RNA (mRNA), which plays a vital role in making proteins that can have a profound impact on an organism. The production of these proteins can vary, depending on both environmental and genetic influences.

The researchers found thousands of mRNAs moving in a bidirectional manner between species. These transcripts represented thousands of different genes. Researchers think this molecular conversation might allow the parasitic plant to direct the host plant to dampen its defense responses.

Since we also contain ancient, and potentially active viral or bacterial transcriptomes in our genes, at least some of the voices we hear are real.

Blood is Blood, But What About Photosynthate?

September 11, 2018September 11, 2018Bhodi Tims

Is it really so odd to consider kin recognition in plants? Plant roots grow more in proximity to genetically related plants (Bhatt) and the recognition of kin is based on chemicals secreted by the roots (Biedrzycki). In a recent paper in New Phytologist, Crepy and Casal noted that plants also react to kin in the aerial portions; first by reorienting leaf growth when growing near kin, but not near unrelated plants of the same species; and secondly, by producing more seeds when interacting with kin vs. nonkin.

Can we then consider plants connected via mycorrhizal associations step families?

References:

Bhatt, MV, Khandelwal, A, Dudley, DA. (2011) Kin recognition, not competitive interactions, predicts root allocation in young Cakile edentula seedling pairs. New Phytologist. 189: 1135-=1142.
Biedrzycki, ML, Jalany, TA, Dudley, SA, Bais, HP. (2010) Root exudates mediate kin recognition in plants. Communicative and Integrative Biology. 3. 28-35.
Crepy, MA and Casal, JJ. (2014) Photreceptor-mediated kin recongition in plants. New Phytologist. 205: 329-338.

It’s in the Dirt

September 5, 2018September 3, 2018Bhodi Tims

: Image via Wikipedia

Well, dirt plus nutrient content. Organic farmers know that it’s really about the soil. In particular, the “living” component of the soil. Researchers are now catching up with findings that help explain why soils on organic farms and in native woodland ecologies have greater concentrations of fungal spores in the soil and greater levels fungal colonization of plant roots – particularly the symbiotic or helpful fungi.

Mycorrhizal fungi form a symbiotic relationship with plant roots, each exchanging benefits with the other. The plant gains phosphorous from the extended “root-like” threads of fungal hyphae, while the fungi absorb glucose stored in plant root cells, which was originally metabolized (made) by the plant during photosynthesis. Additional benefits these fungi provide the plants include enhanced disease resistance, soil stability and structure, as well as nitrogen fixation.

However, the fungus cannot be cultivated in the absence of a host plant root. Commercial farming often suffers from dead soil. The USDA’s Eastern Regional Research Center (ERRC) focuses research on the use of mycorrhizal fungi to improve crop quality and yield. Researchers at this facility try to understand the necessary chemical signal exchanged between plant and fungus required during the various stages of fungal development. Their aim is to grow the fungus on artificial media without the presence of plant roots. Because of the numerous benefits that mycorrhizal fungi provide, commercial farmers hope that a fungal inoculum could then be used to limit the amount of fertilizers applied to large scale crops while still improving plant growth and health.

I’ll come back to the way plant and fungus woo each other, whispering sweet chemical cross talk…