Last call for 2018

There seems to be value in reflection; where we’ve been, what we’ve done. Positive memories bring a nostalgia and warming of the heart. Negative memories call forth a resolve to learn from mistakes or guide us toward paths which avoid repeats. The turn of the year seems as good a place as any to take stock.

As 2018 draws within a few hours of its end it rains here. Seems only fit… it’s rained here quite a bit this year. And it may well be in the process of setting a record for the state. I shouldn’t complain too loudly – it could be snow.

Capsulizing 2018… wrote fewer blog posts… now running at about one a month. Did a bit of travel in the Midwest, mostly to see family. Carried on at work along much the same course as previous years, though did incorporate one wrinkle to be discussed below. Survived the health challenge of a spouse’s gall bladder surgery – which had the side benefit of opening one’s eyes to health care issues on many fronts. Learned a bit of Russian, though I don’t imagine this stacks up to anything else in the mirror. So let’s move on to the wrinkle.

Long ago and far away I did some soybean research as part and parcel of the work toward a Ph.D. in Agronomy. At the time one of the interests was soybean production under dryland farming in areas where rainfall was much less plentiful, indeed was scarcely sufficient for regular crop production. One of our interests was in modulating crop canopy temperatures (to save on water use) by genetic manipulation of leaves and stems. There are a host of simple canopy mutations in the soybean genome that affect how radiation impacts the crop canopy. We were interested in a couple aspects – first, how much of an effect we could expect from individual mutants on water use efficiency; and second, would the various mutants interact with each other in ways we would need to appreciate if we were to deploy more than one.

This work was done in Nebraska. Now I work in Ohio, where, as stated above, rainfall is more than adequate… indeed too much in many years. So little of what I learned about the first aspect has much application here. But the second aspect – interactions (also known as epistasis) – this has been quite useful over the long arc of my career.

About a year ago I saw a presentation about soybean canopy effects on seed protein concentration at different positions within a canopy. Seed protein content is very much in line with what we focus on these days where I work. Those old canopy altering mutations swept back to mind, and suddenly the first aspect of the Ph.D. research seemed relevant even in a production system where water was not in short supply.

Lf1 ln Clark leaf '18 - 2

Five leaflets (vs 3), and Narrow leaflets (vs oval).  Some frogeye leafspot there for good measure.

Several of the mutations mentioned affect leaf characteristics – but two of those seemed particularly promising for the seed protein issue. These are leaflet number and leaflet shape. The more leaflets per leaf will increase light interception, but if leaflets are narrower than normal then light interception is decreased. If you put both characters together you intercept about the same amount of light, but the distribution of light in the canopy is changed. If you’ve done much work in biology you’re already thinking it can’t be that simple. And you’d be quite right. Interactions play at multiple levels and make for lots of surprises as one digs into all the possibilities. But until you do start digging into it, there really is no way of knowing what will happen.

Seed of a few different lines with these mutations was procured and crosses were made in the summer of 2018 to start the process of digging into see what we might find on the issue. This whole process will take many years to complete – so don’t be looking for results in this space any time soon.

Over the summer as we grew the mutant lines so we would have pollen to make the crosses there was a fair bit of interest from the staff about how “weird” these lines look. Great that they have such appreciation for ‘normal’ types that these should look so “weird”. And great too that at least one of guys was fascinated enough about the general concept that he’s taken a fair degree of interest and is already getting impatient for results.

I first started playing with the leaf mutations in 1980. I did manage to earn the Ph.D., so the effort did have one intended effect. But the effects we learned about then didn’t lead to any earth shattering developments and we moved on. It will easily be more than forty years after my first blush with these types before we know how these traits influence seed protein concentration throughout a canopy. But sometimes the human experience has to go around in a circle before something comes from it.

The picture of a soybean leaf shown here was taken in early August here in Ohio.  The soybean line is a ‘Clark’ near-isogenic line with a combination of the Lf1 allele for pentafoliolate leaves (5 leaflets) and the ln allele for lanceolate leaves (narrow shape).  Holes in leaves were kindly provided by Japanese beetles (Popillia japonica) a herbivorous Coleopteran which has been mentioned here at GP in the article about 5 gallons of death.  We love them dearly.  Also in the photo are some smallish gray spots – particularly on the smaller leaflet at 6 o’clock.  If these small spots resemble frog’s eyes you may have a future as a plant pathologist – for indeed the disease is known as frogeeye leafspot (Phytopathologists are so creative!).  This is a fungal disease caused by the fungus Cercospora sojina, which seems to really appreciate wet conditions so has found a home in Ohio.

 

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3 comments

  1. Which just goes to show that knowledge is never wasted…

    Liked by 1 person

    1. Indeed… or for the pessimists in the audience: too soon old and too late smart.

      But I do have to marvel at the convenience of having a memory tucked away inside such a useful space as the backside of our faces. Hard to misplace.

      Liked by 2 people

      1. I still find it difficult to find all my memories. 🙂

        Liked by 1 person

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