Project Description

Problems

Peach gummosisis a significant disease affecting the health of peach trees, primarily caused by fungal infections and environmental stress. It leads to bark cracking and the exudation of gummy substances, severely weakening the trees and even causing death. Current control methods rely on chemical agents and agricultural management, but issues such as drug resistance and environmental pollution persist, leaving a lack of efficient and eco-friendly solutions .

PeachGummosis

Solutions

PlantDiseaseTriangle

The plant disease triangle is a fundamental concept in plant pathology that illustrates the interaction between three key factors required for a disease to occur: the pathogen, the host, and the environment.

We propose to manipulate three key factors required for disease occurrence to prevent peach gummosis:

  1. Pathogen: Apply specific RNA-based biopesticides to inhibit the activity of pathogens;
  2. Host: Improve and promote disease-resistant host varieties;
  3. Environment: Promote pruning (of plants) to improve field ventilation conditions.

Inspiration

Talks with peach growers were most rewarding. They wanted both 'convenient' and 'cost-effective' pesticides.

peach-grower

We have also consulted some experts:

  • Professor Tang (Silicon Gene) clarified RNA pesticide stabilization and cost-cutting challenges, highlighting farmers' purchasing power.
  • Director Chen (Fenghua Honey Peach Institute) noted local gummosis ties to varieties and old methods, stressing R&D must fit local needs.

peach-institute

Learn More

Design

Part I: dsRNAs Design for Interfering Chitin Synthase in Fungal Pathogens

rnai

Given that chitin synthase is essential for cell wall integrity and fungal viability, designing double-stranded RNA (dsRNA) for RNA interference (RNAi) targeting Chitin Synthase in pathogenic fungi, e.g. Lasiodiplodia theobromae is a promising strategy for developing targeted fungal control.

Benefits

  • dsRNA can be designed to act only on specific pathogens or pests, posing no harm to humans or other non-target organisms.
  • RNA-based biopesticides exhibit scalability and can accommodate dsRNAs targeting different organisms.
  • Policy support, shortened R&D cycles, and accelerated time-to-market.

Part II: Overexpression of Chitinase in Peach Leaves

On the other side, chitinase is an enzyme produced by host plants, and upregulating its expression can enhance the plant's resistance to fungal pathogens. When considering non-target organisms like bees, we turn to leaf-specific expression promoters to achieve high-level expression of chitinase only in leaves.

Benefits

  • Even in the juvenile stage of peach trees, farmers can gain some profits by extracting chitinase from the leaves.
  • Pruning is a core measure to control peach gummosis, acting by reducing tree damage, optimizing structure, and lowering infection risks. Farmers will prune actively when they see leaves' optimized functions clearly lead to more income, better quality, and lower costs.
  • The concept of 'once and for all' (achieving a permanent solution with one effort) is not only reflected in the synthesis of functional substances in perennial plants themselves, but also in the long-term ecological adaptation strategies of perennials and the sustainable economic value they bring to human utilization.

leafchitinase

Experiments

1. Our Protocols

2. Our Lab Nootbook

3. Our Results

Outlook

About GumEraser+

Peach gummosis seriously harms peach tree health, mainly triggered by fungal infections and environmental stress.

'GumEraser+' propose to manipulate three key factors required for disease occurrence. To turn this concept into actionable practice, we need to clarify key technical details:

For apply specific RNA-based biopesticides: e.g. delivery method and field application timing.

For high disease-resistant varieties breedings: e.g. the influence on fruit size, sweetness, shelf life, etc.

For...

But...
These will most likely become the research topics for our postgraduate studies.


For More Information

Project Promotion Video

About Fenghua Honey Peach

  • Fenghua (a district of Ningbo, Zhejiang province, China) has a history of over 800 years in cultivating peaches on a large scale. In 1996, it was jointly named the 'Hometown of Chinese Honey Peaches' by the Development Research Center of the State Council and other departments. At present, the main peach varieties grown in Fenghua include 'Baifeng', 'Chiyue', 'Hujing Milu', 'Xinyu', 'Yulu', 'Liangfang', and 'Baili', with a cultivation area of about 2,334.5 hectares. 'Fenghua Peaches' carry the honors of being a National Geographical Indication Agricultural Product and a National Ecological Origin Protected Product, with an annual output value exceeding 500 million yuan[1].
  • In this regions, the economic lifespan of peach trees is typically 15-20 years, with very few exceeding 20 years. On average, it's probably around 15 years, with gummosis being one of the main factors affecting lifespan. Peach gummosis could be physiological or pathological, distinguished by the secretion of dark-brown gum from the stems and shoots of peach trees. According to the plant disease triangle, three key elements must be present for a disease to occur: a susceptible host, a pathogen, and a favorable environment. All three components must interact simultaneously for disease development. If any one of them is missing or not aligned, disease typically won't occur. This model is widely used in plant pathology to understand and manage plant diseases effectively.
  • The hot and humid climate creates favorable conditions that markedly intensify the symptoms of gummosis, thereby aggravating disease progression in susceptible plants. Theoretically greenhouse cultivation could improve the environment - for example by controlling temperature and humidity - this would not only be costly but also couldn't completely avoid other pest and disease risks.

About Chitin Synthase

Chitin is a long-chain polymer of N-acetylglucosamine (a derivative of glucose) and is a key structural component in:

  1. Fungal cell walls.
  2. The exoskeletons of insects and crustaceans.
  3. Some other invertebrates.

Chitin is synthesized by an enzyme called chitin synthase. This enzyme is embedded in the plasma membrane and catalyzes the formation of β-(1,4)-glycosidic bonds between N-acetylglucosamine units. The newly formed chitin chain is extruded into the extracellular space, where it assembles into microfibrils that contribute to mechanical strength and rigidity.

In fungi, chitin synthases are encoded by multiple genes, allowing for different forms of the enzyme that function at various stages of growth and development.

Biotech relevance: Because chitin synthase is absent in plants and animals, it is a potential target for antifungal agents.

About Chitinase

Chitinase (EC 3.2.1.14), a subgroup of glycosyl hydrolases (GH), catalyzes chitin hydrolysis by cleaving the β-1,4 linkage of N- acetylglucosamine. As plant cell walls lack chitin, when chitin - containing pathogens infect plants, chitinase gene expression is activated for PAMP-triggered immunity, so it's a pathogenesis-related (PR) protein. Transgenic expression of chitinases can increase resistance to fungal pathogens[2],[3].

Applications:

  • Agriculture: Engineered chitinases can enhance plant resistance to fungal pathogens.
  • Biocontrol: Chitinase-producing bacteria (like Streptomyces or Bacillus) are used as biopesticides.
  • Medical and pharmaceutical: Potential use in antifungal therapies and allergy treatments (since chitin fragments can trigger immune responses).

Main References

[1] [CN] Fenghua's peach is 'sweet' enough to establish a provincial model.

[2] [EN] de las Mercedes Dana M, Pintor-Toro JA, Cubero B. Plant Physiol. 2006 Oct;142(2):722-30.

[3] [EN] Ze Xu, Jieyu Dai, Liping Liang, et al. Foods 2023, 12(13), 2503.