Episode 99: Reshaping How Agriculture Sees Plant Nutrient Uptake With Dr. James White

Hi, friends, this is John. Welcome back to the Regenerative Agriculture podcast where we talk about all kinds of fun topics related to agronomic science and cultural management practices that can help us improve our soil health and improve the health of food and ultimately the health of us as humans and the livestock and all the landscapes that we care for. I've been looking forward to this conversation for a while. I'm really excited to have Dr. James White back on the podcast. I had him here, I think it's a couple years ago at this point. And I was really excited by his publications of the work that he and his colleagues have been doing describing the rhizophagy cycle, the concept of plants feeding on and getting nutrition from microbes. Because I see this as one of the fundamentals, one of the fundamental pieces that we need to understand and to develop a completely different paradigm, a completely different worldview of how plants get nutrients. Because the contemporary model has been based on the idea that plants get their nutrition primarily from soluble ions in the soil solution. And we know that that model has all kinds of problems because it's obviously not how wild plants and undomesticated ecosystems get nutrition, because soluble nutrients don't exist in large concentrations in unmanaged soils. And so I've been really interested in understanding this phenomena and seeing how we can develop agricultural and agronomic management systems that can give us exceptional levels of plant health and productivity without degrading our soil ecosystems with salt based fertilizers. So I'm really excited to have you back, James. Thank you for being here and for all the incredible work that you've done and continuing to share your knowledge and wisdom. I so enjoyed the conversation we had in the last episode. And I still remember, there were many highlights for me in that conversation, but I still remember when you described that these organisms, such as Fusarium that we consider to be pathogenic, can actually develop symbiotic or collaborative relationships with plants that are not pathogenic relationships dependent on the soil environment. And that was such a profound moment for me. I still remember that, that highlight. So I want to say thank you for being here and tell us a little bit about what you've been working on the last couple of years. I keep hearing about your work everywhere. Now a lot of people are starting to pay attention. So I'm really excited about that.

Well, thank you, John. I'm so glad to be here and to be able to support the work that you're doing and to learn from what you are doing, from what you're teaching. You know what I, what I think just to go off of what you just said about Fusarium and how microbes impact behavior of pathogenic fungi, just to add to that, really, all fungi take in endophytic bacteria. They take them in. If you take for example, a mushroom, we think of mushrooms as well. They just grow right on wood and degrade wood. But in fact, if you look at the structure of the mushroom, you look inside their hyphae, you'll see bacteria in there. So these fungi, even mushrooms, they have their own endophytes and they utilize those endophytes for nutrients. Nitrogen mostly is what it looks like. So that's the fungus connection. Of course, the big picture of that is that, that the behavior of, if you consider a pathogen, the behavior of that pathogen changes when it has bacteria inside it. And we think that's because of the need for nutrients, for nitrogen in particular. And that if the fungus, a pathogen can get its nutrients from endophytic bacteria, it doesn't have to attack plants to get those nutrients. Instead, it really is, and it's a view, it's the kind of principle that you can use to protect plants using microbes and build soils that are healthy and microbes don't cause disease in those soils, the so called suppressive soils. Right.

Yeah. So you just, my goodness, you just raised half a dozen question marks in my mind. So when we're talking about developing disease suppression suppressive soils, I've thought of disease suppressive soils as being these soils that contain suppressive bacteria. So suppressive microbial populations that suppress pathogens from expressing themselves. But what you're describing is actually these are soils that have such abundant bacterial populations that they can supply the nutrients that the fungus requires and that alters the nature of the relationship. So in fact, a disease suppressive soil is not so much about specific types of bacteria or specific strains as it is the ability to provide bacterial nitrogen to the fungus. And a total population. So it's. Total population.

Yeah. And I mean, it's what we're seeing already. You know, I mean, we, we know that. I mean, so far there's no evidence that there's any kind of a silver bullet that you could take one microbe and give it to a plant and that's going to be everything the plant needs. Right. Same with fungi, you know, there's no silver bullet. In fact, they're getting a lot of different microbes going inside them, not just one. So in soils, and you talk about a suppressive soil, it's Going to be a soil that's rich in microbes that work with fungi and plants and a fight.

So I learned something recently that made a lot of sense, but also is such a marvelous idea and I'd love to get your perspective on this. I learned that a fungi, fungal mycelia is a single cell. And I don't. I've really wondered about that. I have this kind of, these conflicting perspectives. This is, I don't know the answer to this, but this is what I was told. And I've marveled at the speed at which bacterial endophytes can move through hungle hyphae. And so it makes sense that it's not cell to cell transport. And I've also learned that the DNA is identical of, let's say a single mycorrhizal fungi that is in some cases miles across. But how does that translate to a fungi being a single celled organism or not?

Well, you have to think of the fungal structure and I mean, the, the main fungus that I'm going to talk about now are the ascomycetes, right? The ascomycetes, a certain group has certain. It's a group of fungi that have certain characteristics. And among those characteristics is that it has septa or cross walls in the haifa. The chain, right? The tubular growth of the fungus. Then it has cross walls there. But the cross walls have, have holes in the middle. They have a pore in the middle. So basically it's just a wall that goes down and then goes back and then there's a hole right in the middle. So there's constant movement of nuclei through that hole, of mitochondria through the hole. And even bacteria go through that hole and they can move between the high feet. It's going to slow them down a little bit because of the septa that are there. But they still have free, free movement. You don't have that hindrance of movement until you look at the mushrooms, the basidiomycetes. The basidiomytes, because they have now plugs in their septa and it's more difficult to move bacteria between the cells. But they still do it. They still do it because those bacteria are important.

So there are multiple cells, but the cell membranes in some of these groups are very open and facilitate free movement back and forth.

Well, I should say something. There are multiple cells, but there are holes between the cells. So the walls, holes in those walls. And it is, I mean, in a sense it's a single cell. But that can be a little bit confusing because there are multiple different genetically different nuclei. In many of those hyphae, they have this process where they will just move DNA from one hypha to the next. And so sometimes you'll get, many times you'll get a hypha network that has multiple nuclei in it, multiple sets of DNA, right? Different genetic nuclei in them. And so it's a little bit. It's almost like a little community. A fungus oftentimes is like a little community in that it has multiple individual nuclei or genotypes in it. Not all this is typically why we single spore fungi, to grow them, because you want to get only one nucleus, right? So we single spore it. But if you don't, they'll be, they may be in a high probability of more nuclei in the, in the hypha than you expected. So more kind of a mixed bag of characteristics.

All right, so this is outside my domain of knowledge, but when you have multiple nuclei, does that also mean that you have, like, how does that translate or correspond to different species exchanging genetic information, different species of fungi or different species of bacteria? With fungi, like what, what does the exchange of genetic information look like?

Well, there is this process called parasex. P A R A S E X. Right, Parasex. And it's supposed to be similar to sex, but sexual reproduction is actually a very organized process. This parasexual process is not organized, at least not as far as we know. Hyphae will just fuse. Nuclei will go in and then they'll be in there. And then at some point this parasects for this to happen, those nuclei will fuse, right? They'll fuse together and then you'll have double the DNA. And then little by little, as the nuclei divide, some chromosomes are thrown off and it goes back down to the original level of DNA in the fungus. So with some variation happening. So this is the parasexual process. We think this happens a lot in nature. A lot of fungi just lost their sexual reproduction capacity completely. And so we think they rely on parasex mostly.

So does this mean that. Would it be accurate to say that these various fungal species that we've identified contain genetic information from many other fungal species in the environment around them? In other words, how do you define the boundaries between various species?

It's very ill defined, isn't it? You know, species still tend to be, I mean, separate in that respect. And typically you tend to have species that don't cross. Right, but that's not a good rule because you have plenty that do cross. And defining the, the separateness more like defining the separateness of an individual. Right. Can you really define the separateness of an individual in fungi? Well, you have to go all the way down to the nuclear level. Right. You can't say, unless you wanted to say that, that a fungus can be a mosaic of different individuals. Right. Kind of a multi personality type condition.

Right.

Flora fungus. Or a fungus. Or a fungus. But yeah. And it does mean that the fungus is particularly plastic in what they're able to do. They have genetic capacity. When they have multiple sets of chromosomes in there, multiple genotypes in there, then they can express those as they need to express them. Right. And so they can partially express if they need to break something down and they don't have a, an enzyme to do it in one of the nuclei, they may have in the other. Right. And then they produce that. And so they're much more capable with those multiple sets of DNA in there. And it's just how fungi work. There's nothing special about them. You know, this is just how they function. This is, this is their biology.

This is another incredible explanation of the amazing resilience that exists in these natural ecosystems and fungus in particular. But I think in these natural ecosystems in general, generals is there. I'm amazed. Frequently when we work with farmers, they begin going down a pathway of managing their soils differently of how rapidly soils recover and how rapidly plant health recovers. Like there's this incredible resilience that once you just, you start unleashing it and getting out of the way, we have this amazing recovery that happens.

You know, just to bring in another topic, it doesn't work if Big Ag controls all the seed supply and they won't let farmers recycle their same seed and grow them year after year on their soil. Right. If they make that illegal, then they have to buy, if they've got to buy a certain type of seed in order to grow it, otherwise they've violated some law or something like that, then they can't recover. They can't heal their crops by growing them in healthy soils.

So you just said it doesn't work if they're relying on purchased seed. I'll use that summary. Are you implying that seed that is grown on foreign soil or soil that isn't biologically healthy? I had understood from our previous conversation that these seeds, even seeds that don't have a functional microbiome, can still recruit organisms from the soil that they're planted into. And obviously that is an energy extensive process that delays the ultimate expression of what those seeds and plants would actually be Capable of. But I'd love to just hear you elaborate on that a little bit. Like when you just said it isn't possible or it doesn't work. Where's the dysfunction coming from?

Well, the dysfunction comes from the fact that seeds that are, and I'm thinking mostly corn now is, in my mind, commercial cultivars of corn. And the way that those are. Cultivars are produced using lots of fertilizers, right. Typically in soils that are poor in microbes because they're fertilizer high fertilizer, high glyphosate and so forth. And the outcome is that plants, if you get these seeds, these seeds, for one thing, they're weaker if you have healthy soils. And this is from the work with corn with Walter Goldstein at the Mondawen Institute in Wisconsin. After a couple of years, if you grow these commercial cultivars after a couple of years on regenerative soils, then you can get back those microbes. If you have good, healthy soils. But you still lose some microbes. Some microbes are still lost. And for example, some of the landrace corn have endophytes in them that keep the corn going, that provide nitrogen from using the histochemical tests that we do provide nitrogen to the plants, but keep the corn growing and green for most of the season, whereas a lot of the cultivateds won't do that. And so the microbes that are lost from commercial varieties may be critical for the best growth of that corn. Right. For low input growth, low disease, stay green. Corn that has lots of nutrients in it. It's got phenolics, got antioxidant, amino acids like lysine and methionine, and. And just basically, you know, if. If it's illegal for a grower, a farmer. And I'm thinking, you know, there's some stuff happening in Africa apparently over the last Dec. Where some laws were passed to attempt to prevent farmers from hanging on to their own seed and sharing their own seeds. You know, so that. That's the kind of thing that could be tremendously destructive to agriculture.

I want to come back and talk about what these microbes are doing in the corn plant, how they're fixing nitrogen, how they're supplying at the plant. I want to do a deep dive there, but let's. Let's bookmark that for the moment. And I want to stay focused on the conversation of. So if you. If you have these landrace varieties that have these beneficial endophytes and they are grown in close proximity with, or perhaps in sequence with commercial Corn varieties. Is it possible to transfer the microbes in those landrace varieties to the more modern varieties?

It's quite easy, actually. We've been playing with that. What we do is to take the leaves of the landrace plants. Right, the leaves. Because we think that the most important microbes go all over the plant. And a lot of the nitrogen fixation, of course, a lot of it is in the roots. Most of it is in the roots. Okay. But some of it's in the leaves. And to try to limit the number of microbes that we use, we take the leaves, young growing leaves, grind those up, extract the SAP out of it. Right. Get the microbes out, and then we take our recipient plant. Okay, so that's from the donor. Right? That's the donor corn plant. The recipient. You take that, we clean it up using Clorox to remove some of the microbes that are already on it. Then we germinate it in the liquid of the cell SAP. Right. Of the. Of the leaves. From the leaves. We germinate them. The roots come out, the shoots come out. They. They're colonized. We take that then, and we transfer that into a garden to compare to the parental material, to kind of categorize or study the effect that the microbes are having on the recipient plant. And it's easy to do. I mean, this is the method, and I keep talking about this because it's the easiest thing in the world, and it's not patentable. This is the Iroquois corn medicine. This is the Iroquois Indians. We're doing the same thing in a very similar way.

I'm familiar with the Iroquois corn medicine, but for those of our listeners who aren't. Tell us a little bit about that story.

Yeah. So the Iroquois had their own way to stimulate their crops using microbes. And what they would do is they would take their corn and they would. To produce the corn seed. And this is probably why it lost microbes, is because they dry it, collect it, dry it year after year. And so there's some microbes being lost. Right. Some microbes are lost even from Indian corn.

And is that because of the drying process?

That's because of the drying process completely. That's the only reason, the drying process. So because the microbiome needs moisture to mature on the seed. Right. That's it. Okay. But there's still plenty there. But what they would do then is they would take their seed to make it, to improve germination. They would go out into nature, into the woods, and they would get these woodland grasses or they would get grasses that were along creeks, along rivers and so forth. Things like phragmites and elimus, Canada wild rye and Virginia wild rye and common reed grass, those very common plants, right? They would take those, dig them up, take the roots, clean some of the dirt off of it, get the dirt off, take those roots, beat them up in water, beat them up.