Cultivated and wild bananas in northern Viet Nam threatened by
devastating fungal disease

Date:
February 14, 2022
Source:
Pensoft Publishers
Summary:
For over 100 years, Fusarium, one of the most important fungal
plant pathogens, has affected banana production worldwide. In Viet
Nam, predictions on its impact are dramatic: an estimated loss in
banana production area of up to 71% within the next 25 years. To
find out what individual species are causing the Fusarium wilt
among Vietnamese bananas, an international research team used DNA
analyses and morphological characterization.



FULL STORY ========================================================================== Fusarium is one of the most important fungal plant pathogens, affecting
the cultivation of a wide range of crops. All over the world, thousands
of farmers suffer agricultural losses caused by Fusarium oxysporum
f. sp. cubense (referred to as Foc for short), which directly affects
their income, subsistence, and nourishment.


==========================================================================
As a soil-borne fungus, Foc invades the root system, from where it moves
into the vascular tissue that gradually deteriorates, until eventually
the plant dies. What makes it particularly hard to deal with is that,
even 20 years after all infected plants and tissue are removed, spores
of it still remain in the soil.

One industry significantly affected by Foc is global banana export,
largely dependent on the cultivation of members of the Cavendish subgroup, which are highly susceptible to some of the Foc strains.

For over 100 years, the fungus has affected banana production worldwide.

Researchers predict it will continue spreading intensively in Asia,
affecting important banana-producing countries such as China, the
Philippines, Pakistan, and Viet Nam.

For Viet Nam, predictions on the impact of Foc for the future
are dramatic: an estimated loss in the banana production area of 8%
within the next five years, and up to 71% within the next 25 years. In particular, the recent rise of the novel TR4 strain has resulted in
worldwide anxiety about the future of the well-known Cavendish banana
and many other cultivars. Fusarium oxysporum f. sp.

cubense is, however, not limited to TR4 or other well-known strains,
like Race 1 or Race 2; it is a species complex that plant pathologists
are yet to fully disentangle.

In Viet Nam, like in the rest of Asia, Africa, Latin America, and the Caribbean, most bananas are consumed and traded locally, supporting
rural livelihood. This means that any reduction in crop harvest directly affects local people's income and nourishment.

It has thus become necessary to find out what are the individual species causing the Fusarium wilt among Vietnamese bananas. Only by understanding
which species are infecting the cultivated bananas can concrete measures
be taken to control the future spreading of the disease to other regions.

Using DNA analyses and morphological characterization, an international
team of researchers from Viet Nam (Plant Resources Center, Vietnam
National University of Agriculture), Belgium (Meise Botanic Garden,
KU Leuven, Bioversity Leuven, MUCL) and the Netherlands (Naturalis
Biodiversity Center) investigated the identity of the Fusarium wilt
infections. They recently published their joint research in the
open-access, peer-reviewed journal MycoKeys.

The study shows that approximately 3 out of 4 Fusarium infections
of the northern Vietnamese bananas are caused by the species
F. tardichlamydosporum, which can be regarded as the typical Race
1 infections. Interestingly, Foc TR4 is not yet a dominant strain in
northern Viet Nam, as the species causing the disease -- F. odoratissimum
-- only accounts for 10% of the Fusarium infections. A similar proportion
of Fusarium infections is caused by the species Fusarium cugenangense -- considered to cause Race 2 infections among bananas.

More importantly, Fusarium wilt was not only found in cultivated bananas:
the disease seemed to also affect wild bananas. This finding indicates
that wild bananas might function as a sink for Fusarium wilt from where reinfections towards cultivars could take place.

========================================================================== Story Source: Materials provided by Pensoft_Publishers. The original
text of this story is licensed under a Creative_Commons_License. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Loan Le Thi, Arne Mertens, Dang Toan Vu, Tuong Dang Vu, Pham Le
Anh Minh,
Huy Nguyen Duc, Sander de Backer, Rony Swennen, Filip Vandelook,
Bart Panis, Mario Amalfi, Cony Decock, Sofia I. F. Gomes, Vincent
S. F. T.

Merckx, Steven B. Janssens. Diversity of Fusarium associated
banana wilt in northern Viet Nam. MycoKeys, 2022; 87: 53 DOI:
10.3897/ mycokeys.87.72941 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220214095747.htm

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