Symbiosis of Insects and Bacteria Turns Plants into Zombies, to Suit Invaders

choi

Symbiosis and parasitism | The Sorceress’s Apprentice; How a bacterium and an insect conspire to take over a plant. Economist, Apr 12, 2014.
www.economist.com/news/science-a ... er-plant-sorceresss"

Note:
(a) Sorcerer's Apprentice
en.wikipedia.org/wiki/Sorcerer%27s_Apprentice
(may refer to, among others, The Sorcerer's Apprentice [qv], the 1797 poem by Johann Wolfgang von Goethe)

(b) “ANYONE who walks in the woods will be familiar with witches’ brooms (pictured). Many trees sport these bushy tumours, which have a variety of causes. An important one is a group of bacteria called phytoplasma that are, in turn, carried from plant to plant by sap-sucking insects such as leafhoppers."
(i) witches’ brooms
(A) “Witch's broom may be caused by many different types of organisms, including fungi, oomycetes, insects, mistletoe, dwarf mistletoes, mites, nematodes, phytoplasmas or viruses.:  Wikipedia
(B) Meinhardt LW et al, Moniliophthora perniciosa, the Causal Agent of witches' Broom Disease of Cacao: What's New From This Old Foe?  Mol Plant Pathol, 9: 577-588 (2008)
www.ncbi.nlm.nih.gov/pubmed/19018989
(“The first WDB [witches’ broom disease] symptoms appear to have been described in the diaries of Alexandre Rodrigues Ferreira (described as lagartão; meaning big lizard) from his observations of cacao trees in 1785 and 1787 in Amazonia, which is consistent with the generally accepted idea that M perniciosa, like its main host T [the initial for genus name Theobroma] cacao, evolved in this region [in other words, Amazonia is where cacao tree came from]. The disease subsequently [spread in Latin America]. In each case, cacao production was catastrophically affected with yield reductions of 50-90%. After the arrival of M [the initial for genus name Moniliophthora] perniciosa[, a fungus,] in Bahia in 1989, Brazil went from being the world's 3rd largest producer of cacao (347 000 tonnes in 1988-1990; c. 15% of the total world production at that time) to a net importer (141 000 tonnes in 1998-2000). Fortunately for chocolate lovers, other regions of the world such as West Africa and South East Asia have not yet been affected by this disease and have expanded production to meet growing world demand (predicted to reach 3 700 000 tonnes by 2010)”)
(C) Neither biochemical nor molecular mechanism is elucidated about how various pathogens cause witches’ blooms. Thus there is no way to tell, at the moment, whether witches’ blooms and flowers-turned bushy leaves share common traits.
(D) "Current WBD control strategies have proved ineffective."
(ii) Phytoplasma (New Latin; First Known Use 1994)
www.m-w.com
(iii) Phytoplasma are a kind of bacterial parasites that have to live inside a plant cell. (I have seen phytoplasma followed by both singular and plural forms of the same verbs.)

(c) "Saskia Hogenhout of the John Innes Centre in Norwich, Britain, has been investigating this symbiosis * * * Her results, now published in PLOS Biology, are a dark tale of molecular mayhem. Dr Hogenhout and her team experimented on Arabidopsis, a type of cress"
(i) Saskia Hogenhout, Cell & Developmental Biology, John Innes Centre
www.jic.ac.uk/staff/saskia-hogenhout/index.html

Her home page contains a video clip (of the same title), leading to
JohnInnesCentre, How plants become zombies. YouTube.com, published on Apr 9, 2014.  
(ii) John Innes Centre
en.wikipedia.org/wiki/John_Innes_Centre
(located in Norwich, Norfolk, England; an independent centre for research and training in plant and microbial science; founded in 1910 with funds bequeathed by John Innes)

(d) her paper:

MacLean AM et al, Phytoplasma Effector SAP54 Hijacks Plant Reproduction by Degrading MADS-box Proteins and Promotes Insect Colonization in a RAD23-Dependent Manner. Public Library of Science (PLOS), Apr 8, 2014
www.plosbiology.org/article/info ... ournal.pbio.1001835
(i) The essence of the paper is as follows: Leafhopper vectors--does not matter which insects as long as they are carriers--transmit phytoplasma. The pathogenic phytoplasma produce SAP54 (all named in this summary are proteins). Plants have "MADS-domain transcription factor" (MTF) family that occupy central positions in the regulation of floral development, without which future flower will become leaf-like, resulting in sterile plants. "SAP54 Interacts with Ubiquitin Binding Proteins" RAD23 (RAD stands for "RADIATION SENSITIVE). SAP54 will adhere to RAD23, and tags MTFs directly for disposal, before the latter even functions to create flowers; SAP54 survives the disposal, comes out alive and tags more MTFs for degradation: "SAP54 may escape degradation via the host UPS [ubiquitin proteasome system] * * * RAD23 resists proteasomal degradation and is released from the UPS to bind other cargo. It is possible that SAP54 resists degradation by associating with RAD23. SAP54 may simultaneously interact with MTFs and RAD23 upon which the MTFs are delivered to the UPS for degradation, whereas SAP54–RAD23 complexes are released to bind more MTFs." (quotation from the section of Discussion)
(ii) You will not understand "ubiquitin" unless you are a biologist. Suffice it to say that ubiquitin marks an unwanted protein for degradation at "proteasome" (a garbage disposal machine inside a cell; composed of protease + Greek soma body).
  
ubiquitin
en.wikipedia.org/wiki/Ubiquitin
(found in almost all tissues (ubiquitously [thus named]) of eukaryotic organisms; discovered in 1975; Nobel Prize for chemistry in 2004)
(iii) MADS-box
en.wikipedia.org/wiki/MADS-box
(section 1 Origin of name)

(e)
(i) Arabidopsis
en.wikipedia.org/wiki/Arabidopsis
(a genus, which includes the species Arabidopsis thaliana, one of the model organisms)
(ii) Arabidopsis thaliana (first described in 1577 by Johannes Thal [last name meaning "valley" in German, as in another surname Rosenthal], a German physician (and named it); In 1753, Carl Linnaeus renamed the plant Arabis thaliana; In 1842, the German botanist Gustav Heynhold erected the new genus Arabidopsis and placed the plant in that genus. The genus name, Arabidopsis, comes from Greek, meaning "resembling Arabis" (the genus in which Linnaeus had initially placed it))  Wikipedia
(iii) -opsis (suffix; Ancient Greek opsis, “aspect, appearance”):
"used to form taxonomic names, often at the level of genus: resembling in appearance"
en.wiktionary.org/wiki/-opsis

(f) leafhopper
en.wikipedia.org/wiki/Leafhopper
(a common name applied to any species from the family Cicadellidae; minute insects)