Tomatoes Are Useful For More Than Just Bruschetta!

In my previous blogs, I have explained my overall goals for my research involving phosphate stress. I hope to learn more about the two main secreted PAPs (12 and 26) found in Arabidopsis and eventually over-express these proteins. However, I recently came across some research with a very similar approach to the issue of declining available phosphate and the need to produce transgenic phosphate-efficient crops.

Dr Gao and her colleagues published a very detailed research paper this past summer in the Plant Soil Journal. Previous studies found a regulatory element, miR399, involved in the phosphate starvation response. The main research focus of this regulatory element has been in tobacco plants. However, Dr Gao wished to evaluate whether miR399s can be over-expressed in tomatoes. From there, they wished to study the phenotypes associated with phosphate stress when this over-expression occurs. 

 

Crops Should Get High On Magic Mushrooms!

What do bacteria, fungi, and cyanobacteria all have in common?

They are all microorganisms currently being researched as possible biofertilizers. 

More specifically, scientists are attempting to isolate phosphate-solubilizing microorganisms. They hope that these microorganisms will be able to mobilize the insoluble phosphate found in our crop soil.

Ok, that sounds easy enough. So what’s the holdup?

Alright Soybeans, You Taste Gross But You Work

When plants find themselves in low phosphorus soil, they have evolved many adaptations that I have not had the chance to discuss yet. Some of these include increased root surface area, decreased rhizosphere pH and increased root exudation of carboxylates.

I am always hearing in the media and in scientific journals how wonderful the soybean is and how it will one day save our croplands. I posted a video below so you can see what I am talking about.  

I get it, it's important, but is it really that special?

Now let’s step back for a second and think about the soybean. It is a legume crop that is reliant on N2 fixation. This fixation involves an increase in cation absorption and a release of protons at the root to compensate for the positive charges when they are in phosphorus rich soil. The opposite interaction occurs when they are in nitrate rich soil.

You’re Purple So Maybe You Can Brighten My Day

 A little background to start today. 

Plants contain a Pi-starvation-inducible (PSI) gene expression and complex morphological, physiological, and biochemical adaptations to low phosphorus. Plants have shown to up-regulate intracellular and secreted acid phosphatases in order to catalyze the hydrolysis of Pi from various phosphate monoesters when in an acidic environment. Purple acid phosphatases (PAPs) are a specific acid phosphatase class characterized by a bimetallic active site that causes a purple color. 29 PAP genes have been identified in Arabidopsis. Both transcriptional and posttranscriptional factors have been implicated in the control of  these PAPs. 

Ok, so maybe I am a bit biased in this post because I work on the above PAPs. To make this post even less credible, the paper I want to discuss is written by a PhD student I know. However, the recent work that has been conducted on PAPs provides some very helpful information about how plants respond to phosphorus deficiency that cannot be ignored simply due to some predispositions. 

Get Over the Transgenic Thing... It Works OK

Production of maize in Brazil has reached 50 million tons in 2009. It produces more maize than any other country in the world, besides USA and China. However despite this monoculture crop, Brazil is still able to maintain the highest biodiversity in the world. 

Cerrado is the main type of soil in Brazil. It is characterized by low fertility, low pH, low phosphorus, high phosphorus fixation, and toxic levels of aluminum. Basically, researchers need to develop plants that are able to deal with all of these conditions, especially the low phosphorus.

Amazing Paper Written by Two Graduate Students. Go Figure

Now this is a research paper.

In order to get my point across about the previous paper being innovative but lacking technique, I found another research article in the World Microbiology Biotechnology Journal that does things right.It covers the same type pf research with the same type of solubilizing bacteria. 

Let's Ask the Soil

It makes sense right? Scientists are always talking about how the problem is not that we do not have enough phosphorus; the problem is that most of what we have is unavailable to plants. Ok… so let’s just transform the phosphorus we have into a form plants can use and call it a day...

                 

 

          

Technology at its best!

How about we just concentrate on plants we KNOW can thrive in low phosphorus conditions for today.

White lupine (Lupinus albus) is a very P-deficient tolerant plant species and thus it can be used for studying its adaptations to low phosphorus. 

When under phosphorus stress, white lupin has been shown to develop many lateral roots that contain several clusters. These clusters are subsequently covered with root hairs. These adaptations all serve to increase the surface area of the roots to allow the crops to absorb more phosphorus. These roots can also release organic acids, as I have previously discussed, to help mobilize the phosphate from its insoluble form. 

 

See I Can be Open-Minded… Well Kinda

In the first post of this blog, I promised that I would talk about more than just phosphate. So before I get into some detailed studies about how scientists plan on dealing with the phosphate decline, I thought I would cover another, some would say more “important”, scarce plant nutrient.

Nitrogen is not only the most expensive necessary nutrient to apply in agriculture, but it can be loss quite easily in the field. The run-off of agriculture nitrogen causes soil and water pollution. It can also cause global warming through emissions of nitrous oxide.

But let’s be honest, nitrogen in agriculture is currently at quite a different place than phosphate. Nitrogen is renewable, whereas phosphate is not because we are never going to have a planet without nitrogen. However, it is still in a problem-state. Agriculture will not run out of nitrogen, but it almost wishes it could...