When the rust settles: Uncovering the movements of coffee leaf rust
disease
Incidence of coffee leaf rust in Vietnam, possible original sources and subsequent pathways of migration

Date:
April 19, 2022
Source:
University of Tsukuba
Summary:
Researchers have found a high incidence of coffee leaf rust
(CLR) disease in Vietnam, the world's second-largest coffee
producer. Potential origins and migration routes were revealed,
as well as a close genetic relationship with several Central and
South American rust fungus populations. These findings will help
to predict future spread of CLR, and highlight the need to consider
seedling sources and human activities in CLR management.



FULL STORY ========================================================================== Coffee is one of the world's most popular drinks, yet there are still
many unknowns in the coffee-growing business. Now, researchers from
Japan have shed new light on the nature of a disease that seriously
affects coffee plants.


==========================================================================
In a study published this month in Frontiers in Plant Science, researchers
from the University of Tsukuba and Ibaraki University have revealed that
coffee leaf rust (CLR) disease is widespread in the main coffee-growing
regions of Vietnam, the world's second-largest coffee producer.

Rusts are plant diseases named after the powdery rust- or brown-colored
fungal spores found on the surfaces of infected plants. CLR fungus,
Hemileia vastatrix, causes CLR disease in Coffea plants -- the source
of coffee beans.

This disease severely affects the plants, resulting in high yield losses
and lowering bean quality; developing effective and practical ways of
managing the disease is essential for mitigating this problem. The best
way to control CLR is by using disease-resistant plant varieties. However, there have been recent reports of CLR outbreaks in coffee-growing regions
where rust-resistant varieties are planted.

"To control this disease, we need to understand rust population
diversity," says senior author of the study, Associate Professor Izumi
Okane. "We must also identify the genetic variations that underpin it,
and anticipate potential future variations." To do this, the researchers examined the occurrence of CLR disease in key coffee-producing regions of Vietnam, assessed the current population structure and genetic diversity
of the CLR fungus via genetic sequencing, and estimated the geographic
region where H. vastatrix first established, as well as its direction
of migration between Vietnam's main coffee-producing areas.

The results showed a high incidence of CLR disease in most of the regions investigated, and that H. vastatrix populations in Vietnam shared a
close genetic relationship with several Central and South American
populations. The study also uncovered potential starting points and
migration routes of H.

vastatrix in Vietnam's coffee-growing regions. The spread of CLR from
northern to southern Vietnam revealed that agents other than wind
and monsoon were involved in moving spores from an infected region to
other areas.

"Our study highlights the need to consider human-mediated activities,
because they may quickly accelerate the genetic diversification of rust
fungi populations," explains Associate Professor Okane.

The results of this study have revealed new information on the genetic diversity of H. vastatrix in Vietnam and Central and South America. The researchers' findings will help to predict the spread of this fungus in
the future. Furthermore, seedling sources and human activities have been highlighted as factors that should be considered in the coffee-growing
industry for the control of CLR disease.

This research was financially supported by Japan Society for the Promotion
of Science (JSPS) KAKENHI Grant Number 20H03006 (IO), the annual fund of
the Biotechnology Center of Ho Chi Minh City and the fund for student
research from the Ministry of Education, Culture, Sports, Sciences,
and Technology of Japan.


========================================================================== Story Source: Materials provided by University_of_Tsukuba. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Cham Thi Mai Le, Izumi Okane, Yoshitaka Ono, Yoshiaki Tsuda, Yuichi
Yamaoka. Incidence of Coffee Leaf Rust in Vietnam, Possible Original
Sources and Subsequent Pathways of Migration. Frontiers in Plant
Science, 2022; 13 DOI: 10.3389/fpls.2022.872877 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220419103220.htm

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