25 April 2015 | Online since 2003



29 May 2014|Arable,Cereal,Crops,News

New understanding as to how plants defend themselves against disease


A new understanding as to how plants defend themselves against some pathogens that cause crop diseases is proposed by researchers from the University of Hertfordshire to help scientists breed new, more successful disease-resistant agricultural crops. The new concept is called effector-triggered defence or ETD.

Breeding agricultural crops for resistance against disease pathogens is essential in the quest to secure global food production. However, despite efforts to control them, crop diseases still account for fifteen percent of the losses in the world’s food production. Farmers spray their crops with fungicides to control these plant diseases, but their effectiveness is limited as disease pathogens mutate to become insensitive to the fungicides.

By exploiting new molecular and genetic insights, the research, done in collaboration with Pierre de Wit from Wageningen Agricultural University in the Netherlands, provides a better understanding of the defence system of crop plants against the damaging pathogens that grow in the spaces between plant cells. This provides new opportunities to improve the effectiveness of breeding crops for resistance against disease.

Dr Henrik Stotz, Marie Curie Fellow and lead researcher from the School of Life and Medical Sciences at the University of Hertfordshire, said: “As traditional methods of controlling crop disease become less effective, the need to breed new strains of crops with an inbuilt resistance to the disease pathogens increases.

“In the same way that humans have developed immune responses against human disease pathogens, crops can be bred for resistance against disease pathogens, but we need to improve our understanding of effective resistance mechanisms within plants. Our research enhances the traditional understanding of the plant defence system and describes a new concept describing how plants protect themselves against the pathogens that grow in the space outside plant cells (the apoplast) – a new concept called effector-triggered defence or ETD.”

Plant defence systems consist of interconnected tiers of receptors, which are found both outside and inside the plant cells. Both sets of receptors sense the invasive pathogen and respond to its intrusion. The two receptor systems have different classes of plant receptor proteins to detect different types of pathogen molecules.

The current understanding of plant defence is that plants, using these receptors, have two forms of defence. Pattern-triggered immunity (PTI) is the first line of defence, operating soon after the pathogen has landed on the plant surface. Before the pathogen has entered the plant, its presence of specific pathogen molecules or patterns is recognised by the host plant’s immune systems. This then activates immune responses to stop the pathogen and so protect the plant from infection.

The second line of defence is referred to as effector-triggered immunity (ETI), this is based on the detection of disease pathogens by the plant’s genes – there is a relationship between the gene in the host plant and the gene in the pathogen. The concept of ETI was developed to describe defence against pathogens that enter into plant cells (e.g. wheat rusts and mildews, potato late blight pathogens) and fits their defence mechanisms well. The presence of the pathogen in the cell activates specific proteins that cause death of both the plant cell and the invading pathogen.

Dr Stotz continued: “This concept of plant ETI does not really explain the second line of defence in the interaction of plant hosts protecting themselves against extracellular fungal pathogens – i.e. those foliar fungal pathogens that get into the leaf of the plant to exploit the space between its cells, known as the apoplast, to retrieve nutrients from the plant. These include the damaging pathogens that cause septoria leaf blotch on wheat, barley leaf blotch, apple scab and light leaf spot on oilseed rape. The ETI concept does not hold for defence against those pathogens that go into the leaf but not into the cells.

“Through our research we discovered that defence against extracellular pathogens (ETD) involves different plant genes from those involved in the defence against intracellular pathogens. We identified some specific resistance genes that code for receptor-like proteis (RLPs) and described how they operated against the pathogens. We feel immunity is too strong a term for this new defence mechanism because these extracellular pathogens can survive and even sexually reproduce on resistant hosts, and so we refer to it as ‘defence’.”

Professor Bruce Fitt, professor of plant pathology at the University of Hertfordshire, added: “This new understanding of plant defence through ETD suggests different operations of specific resistance genes which will help us to be more successful in breeding new strains of crops for resistance. This is essential in the battle for global food security to protect the world’s future food sources.”

Download




Comments


31-05-2014 22:32 PM | Posted by: Christine Smith
I look after roses at a garden centre, and although we are told that roses are disease resistant these days, I am still strung gelling with mildew on our stock! Why is this particular disease so aggressive when we haven't yet found an effective control!

To post comment without approval login or register

Display name

Please enter your name

Email (optional)
Comment

Please enter your comment

Post Comment

Your comment submitted successfully.Please wait for admin approval.

Some error on your process.Please try one more time.



Jobs


15 April 2015
Trainee Sales Executive
My client design and supply their products within the whole construction sector including residential, commercial, retail, ed...

12 April 2015
Apprentice Kennel Hand
Essential duties to include cleaning of kennels and cattery, feeding and grooming of boarders. Must be reliable and confident...

14 April 2015
Graduate Digital Sales Executive
Our client specialises in producing sustainable agriculture, animal health and welfare literature. Graduate Digital Sales Exe...

10 April 2015
Regional Business Manager - Midlands. Ruminant Feed
Previous field sales experience, to farm or to business, in the UK feed or livestock industry is preferred....

14 April 2015
HGV Class 1 Driver
Alan Wedge – Transport Manager A C Shropshire Ltd Green Lodge Farm Forest Road Huncote Leicestershire LE9 3LE....



Top stories you may have missed
10 April 2015 | Agri Safety

The permanent eradication of Bovine Viral Diarrhoea [BVD] in Scottish cattl...


10 April 2015 | Dairy

The abolition of milk quotas in Europe on 1st April has resulted in a numbe...


10 April 2015 | Cattle

The top 14 milk producing countries in Europe will increase their productio...


10 April 2015 | News

Matt Ware is the NFU's head of government and parliamentary affairs, based ...


10 April 2015 | Arable

There is a 'desperate need' to improve farmgate returns given low incomes a...


9 April 2015 | Arable

Rapid stem extension, after a slow start to spring, is likely to create spl...


9 April 2015 | Finance

The time has come for landlords to expect to see reductions in farm rents, ...


8 April 2015 | Cattle

Cogent’s reputation as a source of the highest calibre sires has been enhan...


8 April 2015 | Arable

The spread of exotic and aggressive strains of a plant fungus is presenting...


7 April 2015 | Animal Health

The FSA’s new Food Crime Unit wants the industry to share information, some...