Introduction Roberto A. Gaxiola, Kamesh Regmi and Kendal D. Hirschi. “Moving On Up: H+-PPase Mediated Crop Improvement”. Trends in Biotechnology. Published on January 23, 2016.
The article chosen is “Moving On Up: H+-PPase Mediated Crop Improvement”, written by Gaxiola, Regmi and Hirschi (2016). The article discusses on the increasing the expression of the enzyme H+-PPase in plants can more effectively move sugar, water and nutrients to the roots, fruits, seeds and young leaves and thus increase the plant biomass and yield.
The high content of H+-PPase is reasonable from the perspective of the cell’s energetics. In growing tissue, RNAs, proteins and cellulose are actively synthesized for construction of cells and, as a result, a large amount of PPi is produced as a by-product of the metabolic processes. PPi accumulation in the cytosol to high concentrations inhibits these polymerization reactions. The vacuolar H+ -PPase scavenges the PPi in the cytosol and uses it as a source of energy for active transport of protons into the expanding vacuoles (Maeshima, 2000). In the last decade, overexpression of genes encoding H+-PPases was successful in increasing salt and drought adaptive responses in at least 14 different crops (e.g. alfalfa, barley, cotton, maize, rice, among others) (Fuglsang et al., 2011; Gaxiola et al., 2012). Furthermore, increases in shoot and root biomass, yield, root acidification capacity, and nutrient use efficiencies were also reported (Fuglsang et al., 2011; Gaxiola et al., 2012).
The world population is increasing day by day and there are limitations to provide enough food for every person in the world. The production of foods also being affected by the stress conditions such as drought, climate change and the salinization of fields. To overcome these conditions, the researchers conduct a research to improve the crops production without using a huge land by expressing the H+-PPase enzyme.
Article summary As indicated in the article, H+-PPases are hydrophobic proteins and found naturally in all plants that function as homodimers in the generation of proton gradients across membranes by using the energy from PPi. This gene helps to move photosynthates or molecules made by photosynthesis in the leaves to the places plants need them in order to grow better roots, fruits, young leaves and seeds. It has been proved in the late research as a gene that can enhance the expression in variety of crops. The plants that have higher expression of H+-PPases has been proved to both salt and drought tolerance. Moreover, the researchers found that increasing of H+-PPases in plants also contribute to the positively energetic plant process such as general shoot and root growth, increase the uptake of nutrients and CO2 fixation.
In this article they suggests an important additional role for the H+-PPases in phloem sucrose (Suc) loading and transport functioning as PPi synthase. Active uptake of Suc from the extracellular space is needed for phloem loading of Suc into the sieve element-companion cell (SE-CC). The researchers also suggest that the upregulation of the H+-PPases localized to the plasma membrane of SE-CC increase the PPi supply that facilitate Suc loading and transport from the source to sink tissues. Thus, plants that have higher H+-PPases have the larger and more energized root systems with higher water and nutrient uptake capacities. Moreover, it has the positive effect in some plants that express more H+-PPases such as barley and wheat have salt stress tolerance and display high biomass production and yield.
Critical evaluation This article suggest additional role for the H+-PPases that regulate the uptake of sucrose to enhance the growth of important part of the plant such as roots, shoot, fruits, young leaves and seeds. Thus increase the uptake of water and nutrient for high biomass production and yield. Moreover the plants also express tolerance to stress such as salinity and drought. The authors are really expert in this agriculture biotechnology field since they have been working for it several years and they also have published several articles about the impact of H+-PPases in plants. This article may benefit the agriculture field as to provide a new way to improve the plants tolerance to stress and yield without using a huge land to feeds all people over the world.
Figure showing the process was helpful for readers to understand how the process occurs in the plants. But the methods used to investigate the mechanism of H+-PPases in plants were not well explained. There are no explanation in how they regulate the H+-PPases and how they observed the process occurs in the plants. Furthermore, there are no additional explanations on the terms used in the experiments as usually stated at the end of the article.
A brief explanation on H+-PPases help the readers to better understand the importance of studying the correlation between H+-PPases and how its enhance the stress tolerance in plants. Without the basic understanding of H+-PPases and its role in plants, it is difficult for the better understanding.
In conclusion, Gaxiola, Regmi and Hirschi (2016) have presented a research that could give a new way in the agriculture field on how to improve crops production with upregulation of H+-PPases in plants in order to resist stress condition and increase the biomass and yield production to feeds people population over the world.
References Arizona State University. (2016, March 24). Researcher improves crop performance with new biotechnology: Farmers can use fewer resources to grow food. ScienceDaily. Retrieved October 22, 2017 from www.sciencedaily.com/releases/2016/03/160324145932.htm
Masayoshi Maeshima. (2000, 30 March). Vacuolar H+-pyrophosphatase. ScienceDirect. Retrieved October 22, 2017 from https://doi.org/10.1016/S0005-2736(00)00130-9
Roberto A. Gaxiola, Kamesh Regmi and Kendal D. Hirschi. (2016, 23 January). Moving On Up: H -PPase Mediated Crop Improvement. CellPress, 2016; DOI: 10.1016/j.tibtech.2015.12.016
Roberto A. Gaxiola, Kamesh Regmi, Julio Paez-Valencia, Gaston Pizzio and Shangji Zhang. (2015, September 22). Plant H+ -PPases: Reversible Enzymes with Contrasting Functions Dependent on Membrane Environment. CellPress. Retrieved October 22, 2017 from https://ac.els-cdn.com/S167420521500369X/1-s2.0-S167420521500369X