Phosphorus (P) is an essential macronutrient, and P deficiency limits plant productivity. Recent work showed that P deficiency affects electron transport to photosystem I (PSI), but the underlying mechanisms are unknown. Here, we present a comprehensive biological model describing how P deficiency disrupts the photosynthetic machinery and the electron transport chain through a series of sequential events in barley (Hordeum vulgare). P deficiency reduces the orthophosphate concentration in the chloroplast stroma to levels that inhibit ATP synthase activity. Consequently, protons accumulate in the thylakoids and cause lumen acidification, which inhibits linear electron flow. Limited plastoquinol oxidation retards electron transport to the cytochrome b6f complex, yet the electron transfer rate of PSI is increased under steady-state growth light and is limited under high-light conditions. Under P deficiency, the enhanced electron flow through PSI increases the levels of NADPH, whereas ATP production remains restricted and, hence, reduces CO2 fixation. In parallel, lumen acidification activates the energy-dependent quenching component of the nonphotochemical quenching mechanism and prevents the overexcitation of photosystem II and damage to the leaf tissue. Consequently, plants can be severely affected by P deficiency for weeks without displaying any visual leaf symptoms. All of the processes in the photosynthetic machinery influenced by P deficiency appear to be fully reversible and can be restored in less than 60 min after resupply of orthophosphate to the leaf tissue.
More PhotosynQ related publications are available here
Focusing on how the community is using PhotosynQ technologies. This month we are highlighting Rodrigo Gomez, a researcher at the Institute of Molecular and Cellular Biology of Rosario in Argentina who leads the way in macro and protocol creation on the PhotosynQ platform.
Dr. Gomez first became interested in plant biology while attending high school in Argentina’s third largest city, Rosario, when his teacher assigned him a project on photosynthesis, and from there his interest would grow. This interest led to his earning his Ph.D in Biological Science in the Centre of Studies on Photosynthesis and Biochemistry at the National University of Rosario.
Eventually Dr. Gomez found himself working for the Institute of Molecular and Cellular Biology of Rosario (IBR) under the direction of Dr. Néstor Carrillo, who just so happened to be his Molecular Biology professor during college. Dr. Carrillo’s lab is focused on the study of stress biology in plants and the creation of biotechnology tools to make plants more resistance to such stress. Dr. Gomez’s role in the lab is to construct transgenic tobacco plants that express flavodiiron proteins (Flvs) from cyanobacteria. The aim of the project is to increase plant stress tolerance to high and fluctuating light, and other sources of abiotic stress.
Since Dr. Gomez became involved with the PhotosynQ project early he has seen “all the changes of the devices and the platform over the years.” Dr. Gomez says that he came a big fan of PhotosynQ. In his most recently published manuscript all of the measurements were taken using PhotosynQ. More importantly, having access to PhotosynQ’s open, affordable and flexible tools has helped him find his research field in science. He explained to us that “now I certainly know that I want to continue working in photosynthesis, so I can say that the discovery of MultispeQ/PhotosynQ was decisive for me”.
The field data collection season is just getting started here in the USA. I thought this would be a good opportunity to highlight a feature in the app that may be useful when you are out collecting data: adding notes and photo’s to PhotosynQ measurements.
You never know what you are going to encounter in the field, so when you encounter something worth noting, you need a space to do so. For example, maybe you notice disease symptoms or insect damage on a leaf that you want to record. Or maybe you want to note that the plant you measured appears to be dying.
Adding notes and photo’s in the mobile app
There are two ways to add notes and pictures to measurements: 1) add a picture or note question to your project using the project creation tool or 2) add a note or picture to a completed measurement, before uploading the measurement to the website.
The first option requires that you take a picture or add a note for EVERY measurement. If you take a lot of measurements with photo’s attached, you may notice that your data loads slower in the data viewer. You may also notice that all of your photo’s look quite similar, and may not add much value to your project. Who wants to slow down their PhotosynQ project with 500 nearly identical pictures of soybean leaves?
Another option is to only take notes and pictures when there is an interesting observation you want to record, and you want to limit these pictures or notes to JUST interesting observations.
In the mobile app, you can add notes to any completed measurement as long as the measurement is not submitted. Here’s how:
Navigate to the Measurements tab in the app. After you Accept a measurement you are automatically directly to this screen.
Select the measurement that you want to add a note or picture to.
Once you have selected the measurement of interest, a new top menu will provide you with options to add a note, delete the measurement, upload the measurement or take a picture (from left to right, below).
Complete your note or image and select Save note or OK for a picture.
Upload your measurement.
Viewing notes and photo’s in the data viewer
You can view your notes from the data viewer in the individual datum view or through the spreadsheet tab. In order to view notes or pictures in the spreadsheet view, click on the More menu at the top of the spreadsheet and check the boxes for what you want to see in your spreadsheet.
*You can also add notes and photo’s to the desktop app, see the help article here
Fusarium redolens, a virulent fungus which causes damping off, leaf yellowing, wilting and root rots has recently been devastating cowpea fields in Uganda. This study aimed at identifying cowpea genotypes that are resistant to Fusarium redolens. Therefore, ninety cowpea genotypes were evaluated two times against a highly virulent Fusarium redolens (isolate from Zombo in Paidha district) in the screen house in 2016. Genotype effect was highly significant (P < 0.001) for root rot severity. Based on the Index of Susceptibility (IS), three genotypes (Asontem, Dan1 LA and IT89KD-88) remained resistant (IS < 3.5) over the two screening periods, 72 moderately resistant (3.5 ≤ IS < 6.5) and 11 susceptible (IS ≥ 6.5). Resistance was found to be enhanced by presence of lateral roots above or at the ground level. Further results suggested a difference in genetic control of resistance to root rots and seed rots caused by Fusarium redolens. All the released varieties tested (SECOW 1 T, SECOW 2 W, SECOW 3 B, SECOW 4 W and SECOW 5 T) had moderate resistance to Fusarium redolens. Correlation analysis revealed root rot severity was strongly correlated to disease incidence (+0.64, P < 0.001), to proportion of plants with lateral roots (−0.56, P < 0.001), to amount of leaf chlorophyll (−0.53, P < 0.001) and to proportion of plants that died prematurely due to Fusarium redolens infection (+0.45, P < 0.001). No significant correlation was detected between root rot severity and proportion of plants that germinated. The established resistance could be exploited for improvement of farmer preferred cowpea varieties towards Fusarium redolens resistance in Uganda.
More PhotosynQ related publications are available here
Focusing on how the community is using PhotosynQ technologies. This month we are highlighting Isaac Dramadri, who just completed a PhD program in Plant Breeding and Genetics here at Michigan State University.
Isaac Dramadri was another of our early adopters, who started experimenting with PhotosynQ way back in the fall of 2014 (not to be confused with Isaac Osei-Bonsu, who we profiled here).
Not only was Isaac one of our earliest adopters, he has also been one of our most active users. Since he began experimenting with PhotosynQ, he has collected over 38,000 measurements. That accounts for 5% of all measurements on the PhotosynQ platform!
Isaac came to MSU from Uganda in 2013 to pursue his PhD, which he recently completed. Congratulations Dr. Dramadri!
He began in the greenhouse at MSU, attempting to identify drought tolerant lines in a common bean breeding population. In 2016, he took some MultispeQ Beta’s on the road, introducing PhotosynQ to scientists at the Makerere University Regional Centre for Crop Improvement (MaRCCI) and national agricultural research services. In 2016 and 2017, he conducted field trials at multiple sites in Uganda, collecting photosynthesis phenotypes from hundreds of common bean lines.
The PhotosynQ platform generated a lot of interest in Uganda, where inexpensive options for high throughout in-field phenotyping technologies are limited. This eventually led to a broader collaboration between the Kramer Lab and MaRCCI.
The overarching goal of Isaac’s 3 years of MultispeQ use was to link photosynthetic traits to other agronomic traits and drought recovery in common bean. His preliminary results have shown that it is possible to use PhotosynQ parameters to identify quantitative trait loci related to drought tolerance. This is exciting and we can’t wait to see more of his results as he publishes them in the near future.
Isaac has now returned to Uganda as a cowpea breeder, and we are sure we will continue to work with him. Good luck Isaac!
We have built numerous tools to facilitate discussion among the PhotosynQ community. In this post I am going to give a brief rundown of these options. All of these options have been present on the platform for a while. However, we have recently updated some of these features and have not actively promoted other features. So, here is the tour…
We have recently updated the forums, making two significant changes. First, we changed the forums homepage. Now you can see all of the available forums (left) as well as the most recent activity on the forums (right). Second, we added a new “Measurements, Protocols & Macros” forum. Those of you who posted on the forums may notice that we moved some of your forum posts into this new category.
Have a question? Looking for tips or support from the PhotosynQ community? Please visit our forums!
You can have discussions within a PhotosynQ project. This is a great way for all of the project collaborators to communicate with each other. It can also be a good way for people who are interested in your project to reach out to you. Project discussions are accessible from your project page on PhotosynQ.
Protocol and Macro discussions
The ability to comment on protocols and macro’s gives you an opportunity to interact with the creator of that protocol or macro. Each protocol and macro on the PhotosynQ platform has its own page where you can comment (below left) or you can post comments from the desktop app (below right).
We have identified an error in the Photosynthesis RIDES macro, which is used to process the data from the Photosynthesis RIDES protocol. If you were using this protocol you may have noticed that your NPQt values were a bit higher than expected, or your PhiNO values were a bit lower than expected. This was due to an error in how we determined Foprime, which is key in calculating these parameters.
The good news is that the PhotosynQ platform is built to allow users to correct issues like this, and apply it to data that you have already collected!
We have now changed the macro to correct the error. So, the next time you go to one of your Photosynthesis RIDES projects, you will see the prompt below asking if you want to recalculate your parameters based on updates to the macro. If you choose yes, the updates will be applied to your data. If you choose no, your data will remain in its present form.