Drought-resistant plant genes could accelerate evolution of water-use efficient crops

Drought-resistant plant genes could accelerate evolution of water-use efficient crops

                Scientists have recently done a study on plants that are good at conserving water to see which genes are responsible for this adaptation.  Plants in drought areas thrive by keeping their stomata shut during the day to conserve water and open at night to collect carbon dioxide.  This is known as CAM and is found in plants such as the orchid and pineapple.  It is a proven mechanism for increasing water- use efficiency which allows them to live in drier climates and still survive.  Scientists identified 60 genes that exhibited convergent evolution in the CAM species.  They found that phosphoenolpyruvate carboxylase is an important enzyme responsible for the nighttime fixation of carbon dioxide into malic acid.  Malic acid is then converted to carbon dioxide so photosynthesis can continue to take place during the day.

                The discovery of the PEPC enzyme is important as scientists can study it more in depth to find out exactly how it works.  One day, they may be able to insert it into other plants, especially those that are very water- dependent.  PEPC will make the plants use less water than ever before.  This can change the future of agriculture at is the leading cause of water use on the planet.  I found this article very interesting as it is another stepping stone to saving the planet.  If we can find a way to use less water on earth, there can be many benefits for the entire planet.  Overall, this study can benefit mankind as we can develop new technologies mimicking this water usage efficiency.  I found another article that goes more in depth about CAM and its usefulness to plants and essentially society. 

 

https://www.sciencedaily.com/releases/2017/12/171201122922.htm

https://academic.oup.com/jxb/article/65/13/3425/2877513

 

Circadian clock discovery could help boost water efficiency in food plants

          Research scientists at the Texas A&M AgriLife Research Center have discovered how the circadian clock functions in pineapples. In the study, the researchers identified 1,398 transcription factors, proteins that regulate expression of certain genes in pineapples. Half of the transcription factors were discovered to exhibit diurnal gene expression patterns, meaning that their gene expression is regulated by the time-of-day. The researchers now hope to use this information to learn more about how efficiently all plants, namely food plants, regulate water in their systems.    
      Pineapples function by using CAM photosynthesis, meaning that they only open their stomata during the nighttime to minimize water loss. Other plants, like rice, wheat, soybean and cotton, use C3 photosynthesis, which entails opening their stomata in the daytime. C3 photosynthesis is less efficient than CAM photosynthesis because more water evaporates from a plants’ stomata if they are open in the daytime than if they are open at night.
       The researchers also found individual components of the circadian clock that regulates the CAM photosynthetic activity in pineapples. The next step for the scientists is to confirm the functions of the circadian oscillator, with hopes of understanding more about the genetic mechanisms of highly water-efficient CAM photosynthesis. The main goal of this research is to understand CAM photosynthesis and learn how to apply it to C3 plants, allowing them to use both methods of photosynthesis. If food plants can use the CAM pathway to photosynthesize, they will be able to adapt to changing climates more easily, and grow in locations uninhabitable to them today. 
      Since the human population on Earth is constantly growing, more food sources are always needed. If scientists can figure out how to give C3 plants the ability to also photosynthesize using the CAM pathway, the food plants will become more water efficient and will be able to grow in more places, giving humans a larger food supply. Many people go hungry throughout the world, so, I think that this is a great idea; by making food crops like wheat and rice more plentiful, there will be more food to go around, for humans and animals. 

Article : Circadian clock discovery could help boost water efficiency in food plants

For more information on photosynthetic pathways click here

Juicy Pineapple Genome Provides Insight into Drought Resistance

The pineapple plant is an interesting and complicated plant known to have gone through many evolutionary adaptations in order to thrive in the water-limited environments it is grown in. The plant has a very complicated evolutionary history, which it shares with grasses such as sorghum and rice. Drought has become a major issue that is responsible for a majority of global crop loss and, therefore, researchers have been looking for ways to make currently existing essential crops drought-resistant. Recently an international team of scientists has completed the genome sequence of the pineapple plant, which has allowed for more insight into its evolutionary history which has allowed it to become drought resistant.

Genetically, ancestors of the pineapple and grasses like rice and sorghum experienced several doublings of their genomes and by tracking the remnants of these whole-genome duplications the team was able to trace the evolutionary histories of these drought resistant crops. By doing this the group was capable of finding that the pineapple genome actually has one less whole-genome duplication than the grasses that share common ancestors with the plant, thus making it the best comparison group to study the genetics of drought resistance in plants.

By completing the genome of pineapple plant the researchers also found more information regarding the crassulacean acid metabolism (CAM) method of photosynthesis the plant uses. Pineapples use the CAM method of photosynthesis, in which plants can close the pores in their leaves during the day and open them at night allowing them to lose very little moisture during the day and absorb and fix CO2 at night to release the following day during photosynthesis. The process has evolved independently in 10,000 plant species, and differs from the C3 and C4 pathways of photosynthesis used by crop and tropical plants.  From the completed genome the researchers found that some of the genes that contribute to CAM photosynthesis are actually regulated by the genes the govern the plant's circadian clock. This is the first time scientists have found a link between regulatory elements of CAM photosynthesis genes and the regulation of the circadian clock, which allows the plants to determine the time of day and adjust it's metabolism accordingly.

Finally, the researchers also discovered that CAM photosynthesis evolved strictly through genetic reconfiguration of the molecular pathways of C3 photosynthesis. This means that all plants contain the genes that are needed for CAM photosynthesis and the evolution CAM photosynthesis can be achieved in different plants species by rerouting the plants preexisting pathways. This finding can lead to huge developments in producing drought-tolerant varieties of several essential crops.

I find this article very exciting and interesting. This is article discusses plant genetics in great depth and is very interesting and informative in regards to the evolution of plants genomes and genetics. I find it so interesting to think that by completing a single genome these researchers were capable of discovering the history of the evolution of the pineapple plant and find the genetic process behind how the pineapple plant developed the ability to be drought resistant and perform CAM photosynthesis. The findings are also very interesting and can lead to so many possibilities in producing drought resistant crops.

For a link the original article click here
To find out more about the different types of photosynthesis click here
For more articles regarding the completion of the pineapple genome click here

Orchid genome has been sequenced

The first orchid species to have its genome sequenced is officially P. equestris. Orchids are an incredibly diverse and specialized group and are particularly endangered due to habitat loss and illegal collection. 

P. equestris is the first sequenced plant capable of Crassulacean Acid Metabolism (CAM). Interestingly, when the orchid's CAM loci were compared to those of non-CAM plants the researchers found evidence for gene duplication and loss. Perhaps these mutations led to CAM photosynthesis. The orchid's introns are much longer than those of any sequenced plant, probably due to transposable elements within those introns. Its genes may also help explain the mechanism of self-incompatability in plants. 

The sequencers also found evidence for a paleopolyploidy that may have occurred before orchids became as diverse as they are today. Perhaps this polyploidy helped the orchids to radiate as extensively as they did. 

Ultimately, the sequencing of P. equestris will aid in conservation and breeding of the orchids as they face more habitat destruction. 

link to the article