rice

Taking the kinks out of curves

In a recent paper, researchers have developed a methodology suitable for analyzing the growth curves of a large number of plants from multiple families. The corrected curves accurately account for the spatial and temporal variations among plants that are inherent to high-throughput experiments.

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An example of curve registration.  a The salinity sensitivity (SS) curves of the 16 functions from an arbitrary family, b SS curves after the curve registration, and c the corresponding time-warping functions. The salinity sensitivity on the y-axis of a and b refers to the derivative of the relative decrease in plant biomass

 

Advanced high-throughput technologies and equipment allow the collection of large and reliable data sets related to plant growth. These data sets allow us to explore salt tolerance in plants with sophisticated statistical tools.

As agricultural soils become more saline, analysis of salinity tolerance in plants is necessary for our understanding of plant growth and crop productivity under saline conditions. Generally, high salinity has a negative effect on plant growth, causing decreases in productivity.  The response of plants to soil salinity is dynamic, therefore requiring the analysis of growth over time to identify lines with beneficial traits.

In this paper the researchers, led by KAUST and including Dr Bettina Berger and Dr Chris Brien from the Australian Plant Phenomics Facility (APPF), use a functional data analysis approach to study the effects of salinity on growth patterns of barley grown at The Plant Accelerator® at the APPF. The method presented is suitable to reduce the noise in large-scale data sets and thereby increases the precision with which salinity tolerance can be measured.

Read the full paper, “Growth curve registration for evaluating salinity tolerance in barley” (DOI: 10.1186/s13007-017-0165-7) here.

Find out how the Australian Plant Phenomics Facility can support your plant science research here.

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High-throughput phenotyping at The Plant Accelerator®

 

 

Last chance to secure an internship – apps close tomorrow!

This is your chance to investigate your plant science questions with the support of the highly skilled Australian Plant Phenomics Facility (APPF) team and the incredible technology and infrastructure we have available.

Internships are offered at the APPF in Adelaide and Canberra for enthusiastic, highly motivated postgraduate students with a real interest in our research and technology. Current postgraduate students in the following areas are encouraged to apply:

  • Agriculture
  • Bioinformatics
  • Biology
  • Biotechnology
  • Computer Science
  • Genetics
  • Mathematics
  • Plant physiology
  • Science
  • Software engineering
  • Statistics

Interstate students are strongly encouraged to apply!

We offer postgraduate internship grants which, in general, comprise:

  • $1,500 maximum towards accommodation in Adelaide or Canberra, if required
  • $500 maximum towards travel / airfare, if required
  • $10,000 maximum toward infrastructure use

The APPF has identified a number of priority research areas, each reflecting a global challenge and the role that advances in plant biology can play in providing a solution:

  • Tolerance to abiotic stress
  • Improving resource use efficiency in plants
  • Statistics and biometry
  • Application of mechatronic engineering to plant phenotyping
  • Application of image analysis techniques to understanding plant form and function

Students proposing other topics will also be considered.

APPF postgraduate internship grants involve access to the facility’s phenotyping capabilities to undertake collaborative projects and to work as an intern with the APPF team to learn about experimental design, image and data analysis in plant phenomics.

Selection is based on merit. Applications are assessed on the basis of academic record, research experience and appropriateness of the proposed research topic. Interviews may be conducted.

Postgraduate students are encouraged to contact APPF staff prior to submitting their application to discuss possible projects.

APPLICATIONS CLOSE:  31 March 2017. For further information click here.

 

Why apply for an internship with the APPF?

Well, aside from the fact we are a pretty nice bunch…

PhD student Rohan Riley, from Western Sydney University, undertook his research at APPF’s Adelaide node (The Plant Accelerator®) after being awarded a Postgraduate Student Internship Grant with us in 2015.

His research attempted to explain the unpredictability of plant growth responses in terms of resource limitation by introducing fungal communities to plants which are isolated from soils containing high or low levels of salinity and analysing the effects on plant stress at the phenotypic level.

This is what he had to say about his experience:

”Using daily phenotyping following the application of salt stress and controlled watering-to-weight in The Plant Accelerator® allowed for an unprecedented resolution and range of plant genetic changes in response to combinations of nutrient level, salinity and two different fungal communities that would not otherwise be achievable in a regular greenhouse,” said Rohan.

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”As a PhD student with limited experience in greenhouse experiments, the highly controlled growth conditions, large-scale automation, digital imaging and software technology (high-throughput phenotyping) at The Plant Accelerator® provided me with the work-space, expertise and technical support to make a complicated experiment possible.”

“It has been an amazing experience to conduct this experiment at The Plant Accelerator®. I am walking away from the facility with a big smile on my face, an incredible dataset for my PhD research and invaluable experience in greenhouse based plant research.”

To find out more about Rohan’s research:  https://www.researchgate.net/profile/Rohan_Riley

A better way to tackle environmental variation in your greenhouse research

Statistics prove the smart way to deal with variation in your controlled environment greenhouse.

Plant phenomics allows the measurement of plant growth with unprecedented precision. As a result, the question of how to account for the influence of environmental variation across the greenhouse has gained attention.

Controlled environment greenhouses offer plant scientists the ability to better understand the genetic elements of specific plant traits by reducing the environmental variances in the interaction between genetics and environment.

But controlled environments aren’t as controlled as they seem – variation does exist. For example, some days are cloudy, some are not. The sun, as it crosses the sky, casts shadows differently on plants, depending on their position within the greenhouse. In fact, a recent study by colleagues at INRA in Montpellier showed significant light gradients within a greenhouse and provided sophisticated tools for understanding how much light each plant receives.

One practice for dealing with variation has been to rearrange the position of the plants around the greenhouse during the experiment, however, there is a better way.

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Rice plants growing in The Plant Accelerator® at the Australian Plant Phenomics Facility’s Adelaide node

The automated high-throughput phenotyping greenhouses at The Plant Accelerator® are controlled environment facilities which use sensor networks to identify and quantify environmental gradients (light, temperature, humidity) in the greenhouses. To further tackle environmental variation, Chris Brien, Senior Statistician at The Plant Accelerator®, led a study that showed good statistical design and analysis was key to accounting for the impact of environmental gradients on plant growth. It was argued that rearranging the plants during the experiment makes it impossible to adjust for the effect of gradients and should be avoided.

The study involved a two-phase wheat experiment involving four tactics in a conventional greenhouse and a controlled environment greenhouse at The Plant Accelerator® to investigate these issues by measuring the effect of the variation on plant growth.

To learn more about Chris’s study read the full paper here.

To discuss the benefits of good statistical design contact Chris Brien.

To access The Plant Accelerator® for your research:  The Plant Accelerator® at the Australian Plant Phenomics Facility (APPF) is available to all publicly or commercially funded researchers. We have a full team of specialists including statisticians, horticulturalists and plant scientists who can provide expert advice to you when preparing your research plans.

 

 

Professor Mark Tester to talk plant science in Adelaide

Professor Mark Tester from King Abdullah University of Science & Technology (KAUST), Saudi Arabia, will present a talk in Adelaide this March:

“Into the field and into the genome – increasing salinity tolerance of crops”

Time:  Wednesday 8 March, 3.30pm – 4:30pm
Venue:  Hosted by The University of Adelaide, Plant Science Department, the talk will be held in the Plant Genomics Centre seminar room (Waite Campus, The University of Adelaide, South Australia) with drinks and nibbles afterwards. All are welcome.

About the speaker

Mark Tester is Professor of Bioscience at KAUST. After a PhD in Cambridge and lectureship there, he went to Adelaide, as a Research Professor in the Australian Centre for Plant Functional Genomics and Director of the Australian Plant Phenomics Facility. Mark was part of the team that led the establishment of this Facility, a $55m organisation that develops and delivers state-of-the-art phenotyping facilities, including The Plant Accelerator, an innovative plant growth and analysis facility. In his research group, forward and reverse genetic approaches are used to understand salinity tolerance and improve this in crops such as barley and tomatoes. His aspiration is to develop a new agricultural system where brackish water and seawater can be unlocked for food production.

Abstract

One-third of the world’s food is produced under irrigation, and this is directly threatened by over-exploitation of water resources and global environmental change. In this talk, the focus will be on the use of forward genetics to discover genes affecting salinity tolerance in barley, rice and tomatoes, along with some recent genomics in quinoa, a partially domesticated crop with high salinity tolerance. Rather than studying salinity tolerance as a trait in itself, we dissect salinity tolerance into a series of components that are hypothesised to contribute to overall salinity tolerance.

For barley, two consecutive years of field trials were conducted at the International Center for Biosaline Agriculture, a site with sandy soil and very low precipitation. Drip irrigation systems allowed the control of salinity by supplying plots with low (1 dS/m) and high salinity water (17 dS/m). A barley Nested Association Mapping (NAM) population developed by Klaus Pillen has been used to dissect physiologically and genetically complex traits in response to salt stress. Ten traits related to yield and yield components (e.g. days to flowering, harvest index, 100 seed mass) were recorded and five stress-indices were derived from each of these measurements. We have identified two significant loci located on the long arms of chromosomes 1H and 5H, which are both associated with several traits contributing to salinity tolerance, namely days to flowering, days to maturity, harvest index and yield.

For tomatoes, the focus is on genetics of tolerance in wild tomatoes, specifically Solanum galapagense, Solanum cheesmaniae and Solanum pimpinellifolium. An association genetic approach is being taken. High quality genome sequences have been made, and genotyping-by-sequencing undertaken. Tomatoes have been phenotyped in The Plant Accelerator and in the field, and analyses are currently in progress.

The application of this approach provides opportunities to significantly increase abiotic stress tolerance of crops, and thus contribute to increasing agricultural production in many regions.

Mark is in Adelaide between Mon 6th and Sun 12th March. If you would like to meet with Mark, please contact him directly: mark.tester@kaust.edu.sa

The Plant Accelerator

Plant phenotyping research projects facilitated by The Plant Accelerator vary from large scale screening of early growth, to salinity tolerance and water and nutrient use efficiency. Possible applications are diverse with respect to the measured traits and plant species studied. Please contact our experts to discuss how your research might benefit from the capabilities and services provided by The Plant Accelerator.

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The Plant Accelerator®,  Australian Plant Phenomics Facility, Adelaide, South Australia

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)