Robert Furbank

International consortia tackle the global challenge to increase wheat yields at the APPF

Field of ripe wheat

Two international consortia of scientists from the United States, Great Britain, Mexico and Australia are currently carrying out research projects of global importance at the Australian Plant Phenomics Facility’s (APPF) Adelaide node for the International Wheat Yield Partnership (IWYP).

The first research project, Improving Yield by Optimising Energy Use Efficiency, is phenotyping an Excalibur x Kukri RIL population to determine genetics controlling energy use efficiency (EUE) in wheat. The aim is to identify genetic loci and markers to enable breeding of high-yielding germplasm with:

  • low rates of leaf respiratory CO2 released per unit growth,
  • optimised levels of sugars, organic and amino acids for growth, and
  • increased biomass at anthesis.

More than 85-90% of the energy captured by plants is used in high-cost cellular processes, such as transport of nutrients and respiration, meaning about only 10-15% is allocated to yield. Thus, any small gain in energy redistribution and use for a costly process can have a marked positive impact on biomass accumulation and yield.

Improvements in EUE can be achieved at the cell, tissue and whole-plant level, with respiration being a prime target.

“Our initial screening of 138 Australian commercial cultivars revealed a two-fold variation in rates of leaf respiration, three-fold variation in the ratio of respiration to growth rate during early development, and significant heritability of 35%. This demonstrates there is untapped genetic variation in EUE amenable to fine-tuning and optimisation of biomass accumulation in the lead-up to anthesis, with concomitant positive knock-on effects on yield”, said Australian National University’s Barry Pogson, Project Lead and Director of the ARC Centre of Excellence in Plant Energy Biology (AUS).

The project has partners at University of Western Australia (AUS), CIMMYT (MEX) and  the University of Adelaide (AUS).

The second research project, AVP1, PSTOL1 and NAS – Three High-Value Genes for Higher Wheat Yield, aims to enhance wheat yield by exploiting and building synergy of three high value genes (AVP1, PSTOL1 and NAS) and enabling molecular breeding by:

  • developing two-gene and three-gene pyramiding combinations of AVP1, PSTOL1 and NAS using available transgenic wheat lines and quantifying the additive effects on yield in multi-location field and greenhouse trials (as a proof of concept),
  • identifying wheat orthologs and allelic variants of TaAVP1, TaPSTOL1 and TaNAS, and designing molecular markers to the best alleles for marker-assisted breeding,
  • providing basic understanding of the physiological and molecular mechanisms behind improved yield and selecting wheat lines with the best allelic combination and field performance, and
  • assessing the necessity for using genome editing technologies to optimise gene function and enhance positive effect on wheat yield by modifying expression of the wheat alleles.

The genes Vacuolar Proton Pyrophosphatase 1 (AVP1), Phosphorus Starvation Tolerance 1 (PSTOL1) and Nicotianamine Synthase (NAS) have been shown to improve plant biomass production and grain yield. Over-expression of these genes results in improved biomass production and grain yield in a range of plant species, including cereals (rice, barley, wheat), in optimal growing conditions. The enhanced yield of the plants is believed to be due to improved sugar transport from source to sinks (AVP1), enhanced root growth and nutrient uptake (AVP1, PSTOL1) and increase in shoot biomass and tiller number (AVP1, PSTOL1, NAS2).

“Identifying and pyramiding the wheat orthologues of these high-value genes provides a real opportunity to produce wheat with significantly improved field performance and higher grain yield,” said Project Lead, Stuart Roy, from the University of Adelaide (AUS).

The project has partners at University of Melbourne (AUS), Arizona State University (USA), Cornell University (USA), University of California, Riverside (USA) and Rothamsted Research (GBR).

These extensive projects will continue throughout 2017 and into 2018.

 

Why is this research so important?

Wheat is the most widely grown of any crop globally, providing 20% of daily calories and protein. By 2050 wheat demand is expected to increase by 60%. To meet this demand, annual potential wheat yield increases must effectively double – an exceptional challenge.

In November 2012, funding agencies and organisations from the G20 countries agreed to work together and formed the global Wheat Initiative to develop a strategic approach to supporting research that would lead to dramatically increasing the genetic yield potential of wheat.

An essential pillar of this strategy is the International Wheat Yield Partnership (IWYP), a novel collaborative approach, enabling the best scientific teams from across the globe to work together in an integrated program to address the challenge of raising the genetic yield potential of wheat by up to 50% in the next two decades all over the world. IWYP builds on the initial research concepts of the Wheat Yield Consortium established by CIMMYT.

To deliver increased wheat yield, a combination of fundamental bioscience and applied research will be needed. IWYP will deliver this through a focused program of research to develop new knowledge, models and wheat lines suited to multiple environments ensuring global gains in wheat yields are achieved.

IWYP will target six key research scope areas:

  • uncovering genetic variation that creates the differences in carbon fixation and partitioning between wheat lines,
  • harnessing genes from wheat and other species through genetic modification to boost carbon capture and fixation to increase biomass production,
  • optimising wheat development and growth to improve grain yields and harvest index,
  • developing elite wheat lines for use in other breeding programs,
  • building on discoveries in wheat relatives and other species, and
  • fostering breakthrough technology development that can transform wheat breeding.

The “IWYP Science Program” provides a unique plan to generate new discoveries and provides for their rapid incorporation into wheat crops grown throughout the world. IWYP’s overarching aims are to stimulate new research, amplify the output from existing programs and make scientific discoveries available to farmers in developing and developed nations.

 

The Australian Plant Phenomics Facility

The APPF provides state-of-the-art phenotyping tools and expertise to help academic and commercial plant scientists from Australia and around the world understand and relate the performance of plants to their genetic make-up. Research facilitated at the APPF is leading to the development of new and improved crops, more sustainable agricultural practices, improved maintenance and regeneration of biodiversity in the face of declining arable land area and the challenges of climate change. Our services.

Do you need access to plant phenotyping capabilities? The PIEPS scheme can help!

Do you have an exceptional plant science research project destined to deliver high impact outcomes for agriculture? The Phenomics Infrastructure for Excellence in Plant Science (PIEPS) scheme was announced in May and is open to all publicly funded researchers. Emphasis is placed on novel collaborations that bring together scientists preferably from different disciplines (e.g. plant physiology, computer science, engineering, biometry, quantitative genetics, molecular biology, chemistry, physics) and from different organisations, within Australia or internationally, to focus on problems in plant science.

The PIEPS scheme involves access to phenotyping capabilities at the Australian Plant Phenomics Facility (APPF) at a reduced cost to facilitate exceptional research projects. Researchers will work in partnership with the APPF to determine experimental design and optimal use of the equipment. Our team includes experts in agriculture, plant physiology, biotechnology, genetics, horticulture, image and data analysis, mechatronic engineering, computer science, software engineering, mathematics and statistics.

Applications are assessed in consultation with the APPF’s independent Scientific Advisory Board. Selection is based on merit.

Don’t miss this an outstanding opportunity to gain access to invaluable expertise and cutting edge technology to accelerate your research project and make a real impact in plant science discovery.

Applications close:  30 September 2017

For more information and to applyAPPF Phenomics Infrastructure for Excellence in Plant Science (PIEPS).

To find out how the APPF can support your research, contact us.

Learn more about projects at the Australian Plant Phenomics Facility and keep in touch.

 

 

Sun protection and diversity could be key to more productive rice crops

With a rapidly growing population, improving the yield of global food staples such as rice has become an urgent focus for plant scientists.

In a recent study published on Plant Physiology, scientists have discovered they can improve rice productivity by selecting rice varieties that are better at capturing sunlight to produce grains instead of reflecting it as heat.

The team, which included Dr Xavier Sirault from the Australian Plant Phenomics Facility’s High Resolution Plant Phenomics Centre (APPF – HRPPC), focused on rice’s natural diversity by using traditional breeding techniques to select cultivated varieties – or cultivars – that are better at converting sunlight into food.

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“We studied hundreds of plants from five rice cultivars and found that there is variation between these varieties in relation to the quantity of light they use for growth or dissipate as heat. Some of them are capable of converting more sunlight into chemical energy, producing greater leaf area over time,” said lead researcher, Dr Katherine Meacham.

When leaves intercept sunlight, this sunlight is either; 1) absorbed by the leaf and converted via the process of photosynthesis into the plants own components; leaves, grains, roots, etc. 2) dissipated as heat as an strategy to protect the proteins of the plant from sun damage (photo-protection) or, 3) re-emitted as fluorescent light. In this study, the researchers measured fluorescence to infer the quantity of energy that is either converted into food or dissipated as heat.

“Recently scientists in the US found that they can produce transgenic plants that are better at catching sunlight without getting sun damage. Our work shows that this is also achievable by taking advantage of the natural variation of rice plants,” says Professor Robert Furbank, Director of the ARC Centre of Excellence for Translational Photosynthesis and one of the authors of this study.

“What is new about our research is that scientists had previously thought there was not much variation in how efficiently leaves could absorb and use light, and the reason for this is that they were not considering the full picture and measuring the plants throughout the entire day under natural illumination. We revealed that there are considerable differences between the five rice cultivars under moderate light and that means that there is room for selecting the most efficient plants,” said Professor Furbank.

“We found that there is room for improvement in some cultivars that can result in more photosynthesis without risking the plant’s protection strategies against sunlight damage.

The scientists measured fluorescence by clipping light receptors on leaves throughout a whole day to get a full picture of how the plant uses sunlight.

Traditional breeding for photosynthetic traits has not been a common strategy in any major cereal crop, in part due to the difficulty in measuring photosynthesis in thousands of plants. However, rapid screening tools are now available to study the interaction between the genes and the way they interact with the environment.

“Using unique facilities at the Australian Plant Phenomics Facility’s High Resolution Plant Phenomics Centre we were able to follow chlorophyll fluorescence in rice canopies throughout the entire day under natural illumination. This gave us completely different results when compared to the usual 30 min measurement of leaf level light use efficiency. By combining this with digital biomass analysis using PlantScan, we could link light use efficiency with growth, revealing genetic variation in rice varieties not previously detected,” said Professor Furbank.

“Our next step is to find varieties with superior photo-protection. We can directly use these for breeding and find the genes responsible. We have the capacity to screen many thousands of rice varieties for which we have gene sequence through the International Rice Research Institute,” said Dr Meacham.

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Measuring photosynthesis.  Photo credit:  International Rice Research Institute (IRRI)

 

 

More salad please!

With indoor-vertical farming on the rise, lettuce production can be customised more than ever, by choosing the right varieties, temperature, lighting and nutrient supply to produce the leaves consumers want. Achieving this goal requires optimisation of numerous components and a recent collaborative study between the USA and Australia, published in Frontiers in Plant Science, has proven optical sensors can be used to evaluate lettuce growth, color and health non-destructively.

The research team, Ivan Simko and Ryan Hayes from the US Department of Agriculture and Robert Furbank from the ARC Centre of Excellence for Translational Photosynthesis and formerly Australian Plant Phenomics Facility – High Resolution Plant Phenomics Centre, designed the study to test the feasibility of using optical sensors for physiological evaluation of lettuce plants in early stages of their development. The method developed can help in breeding programs and optimising farming practices to meet the requirements of an increasingly demanding market.

Read the full study, Non-destructive phenotyping of lettuce plants in early stages of development with optical sensors, published in Frontiers in Plant Science, here.

Or read the abstract here:

Abstract

Rapid development of plants is important for the production of ‘baby-leaf’ lettuce that is harvested when plants reach the four- to eight-leaf stage of growth. However, environmental factors, such as high or low temperature, or elevated concentrations of salt, inhibit lettuce growth. Therefore, non-destructive evaluations of plants can provide valuable information to breeders and growers. The objective of the present study was to test the feasibility of using non-destructive phenotyping with optical sensors for the evaluations of lettuce plants in early stages of development. We performed the series of experiments to determine if hyperspectral imaging and chlorophyll fluorescence imaging can determine phenotypic changes manifested on lettuce plants subjected to the extreme temperature and salinity stress treatments. Our results indicate that top view optical sensors alone can accurately determine plant size to approximately 7 g fresh weight.

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Comparison of the size and the colour of plants cultivated at optimal (OPT), low (COLD) and high (HOT) temperatures (experiment 3). Plants were initially grown at OPT for 10 days and the either continuously kept in OPT or transferred to COLD or HOT for 8 days. Sides of the square pots are 68mm long.

Hyperspectral imaging analysis was able to detect changes in the total chlorophyll (RCC) and anthocyanin (RAC) content, while chlorophyll fluorescence imaging revealed photoinhibition and reduction of plant growth caused by the extreme growing temperatures (3 and 39°C) and salinity (100 mM NaCl). Though no significant correlation was found between Fv/Fm and decrease in plant growth due to stress when comparisons were made across multiple accessions, our results indicate that lettuce plants have a high adaptability to both low (3°C) and high (39°C) temperatures, with no permanent damage to photosynthetic apparatus and fast recovery of plants after moving them to the optimal (21°C) temperature. We have also detected a strong relationship between visual rating of the green- and red-leaf color intensity and RCC and RAC, respectively. Differences in RAC among accessions suggest that the selection for intense red color may be easier to perform at somewhat lower than the optimal temperature.

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Genomic position of the quantitative trail locus (QTL) for light green colour (qLG4) on linkage group 4. Visual rating of the green colour intensity was performed on adult plants in field, while the relative chlorophyll content (RCC) was determined from hyperspectral reflectance measured on cotyledons of seedlings cultivated in plastic boxes (experiment 7). The orange line parallel with the linkage map shows the significance threshold (a = 0.05). The allele for light green colour and low RCC originates from cv. La Brilliante. Detailed description of the linkage map for this population and its construction was published previously (Hayes et al., 2014; Simko et al., 2015b). Distance in cM is shown on the right site of the linkage map. LOD, logarithm of odds.

This study serves as a proof of concept that optical sensors can be successfully used as tools for breeders when evaluating young lettuce plants. Moreover, we were able to identify the locus for light green leaf color (qLG4), and position this locus on the molecular linkage map of lettuce, which shows that these techniques have sufficient resolution to be used in a genetic context in lettuce.

Citation

Simko I, Hayes RJ and Furbank RT (2016) Non-destructive Phenotyping of Lettuce Plants in Early Stages of Development with Optical Sensors. Front. Plant Sci. 7:1985. doi: 10.3389/fpls.2016.01985