References

Primary References

McNeal, J R, Arumugunathan, K, Kuehl, J V, Boore, J L, and dePamphilis, C W. 2007. Systematics and plastid genome evolution of the cryptically photosynthetic parasitic plant genus Cuscuta (Convolvulaceae). BMC Biology, 5(55).

In this article, McNeal describes and tests the phylogeny and steps of plastid genome change in the genus Cuscuta.  Cuscuta pentagona is not directly studied in these experiments, but the genus is described in depth.  According to McNeal, Cuscuta is a paraphyletic group.  There are subgenera determined by morphological differences in style and stigma.  It is difficult to distinguish between species of Cuscuta because of the few morphological characteristics—as it is lacking roots and typically noticeable leaves.  This difficulty is described as an introduction to the genome mapping experiment.  Other species of Cuscuta are discussed in more depth due to their usefulness in the experiment.  This source clearly outlines the genetics of the genus Cuscuta and its loss of certain genes throughout speciation.  This source is particularly useful for its descriptions of Cuscuta and the explanation of the genus’s morphology and life cycle.

 

Revill, M W, Stanley, S, and Hibberd, J M. 2005. Plastid genome structure and loss of photosynthetic ability in the parasitic genus Cuscuta. Journal of Experimental Botany, 56(419), 2477-2486.

This study focuses on the plastid genome of 15 species of Cuscuta, one of which is Cuscuta pentagona.  Revill believes, due to much evidence in similar species and in Cuscuta itself, that Cuscuta may be losing its photosynthetic abilities and have a shrinking plastid genome.  Each of the 15 species of Cuscuta is studied within the experiment to see if certain clades are losing the specific photosynthesis genes faster than others.  The impending loss of photosynthesis is due to the parasitic nature of Cuscuta.  For most of its energy, Cuscuta relies on its host plant.  Cuscuta wraps around its host and leaches nutrients from the host’s phloem.  The stem of Cuscuta is still thought to be somewhat photosynthetic.  I felt this article to be very informative on the nature of parasitic plants.  The introduction explains the premise for the experiment with clarity and detail.  The experiment seems sound and well documented.

 

Runyon, J B, Mescher M C, and De Moraes, C M. 2006. Volatile chemical cues guide host location and host selection by parasitic plants. Science, 313(5795), 1964-1967.

Runyon, et al. explains methods by which parasitic plants find a host.  Cuscuta pentagona was used to test and best demonstrate methods by which a host plant was located and selected.  In Runyon’s experiment, dodder was attracted to a tomato plant at only a few centimeters germinated.  It was determined that the attraction was to the plant’s volatile chemical excretions.  There was also a difference between hosts, as one compound of wheat repelled dodder.  The adaptation of dodder to detect a favorable host plant at an early time reflects on its lack of root system and limited photosynthesis.   This source is thorough in explaining methods by which dodder locates a host plant and why Cuscuta  as a parasitic plant would need to locate a certain host early in growth.

 

Sherman, T D, Bowling, A J, Barger, T, and Vaughn, K C. 2008. The vestigial root of dodder (Cuscuta pentagona) seedlings. International Journal of Plant Sciences, 169(8), 998-1012.

This article discusses the root of dodder, Cuscuta pentagona, focusing on the seedling stage of life.  The roots of Cuscuta are different from many other genera of dicots.  The root is lacking many structures, which are discussed in detail. The “root” may not even be considered a root, but rather something slightly less.  The modified root may have evolved to allow the shoot more means for growth in a shorter time, making Cuscuta a more threatening parasite.   The lack of typical structures also causes Cuscuta to be reliant on its parasitism.  Sherman’s research on the germination and physiology of Cuscuta pentagona is documented in this article.  Sherman’s work is well documented and the meanings of his findings are spelled out clearly.  The information on root and shoot germination and physiology gives insight on Cuscuta’s parasite-host relationship as it pertains to the structure of the plant itself. 

Wright, M, Welsh, M, and Costea, M. 2011. Diversity and evolution of the gynoecium in Cuscuta (dodders, Convolvulaceae) in relation to their reproductive biology: two styles are better than one. Plant Systematics & Evolution, 296(1/2), 51-76.

In this article, Wright looks at the gynoecium of Cuscuta to determine the phylogeny.  Because species of Cuscuta are very similar, stigma and style morphology has been used to classify and differentiate.  The gynoecium is part of these structures.  Many species of Cuscuta were studied.  The morphology was used in this experiment.  Microscopic views of the gynoecium tissue were viewed.  Characteristics were chosen to split the genus further.  Wright found that genera with two types of gynoecium or unequal gynoecium fared better.  This is a morphological adaptation that allows more opportunity for new species to evolve.  Wright found that the best way to distinguish between Cuscuta species is indeed to use the gynoecium characteristics.  He found that certain characteristics work to classify Cuscuta at different levels.  This source give information about how Cuscuta species are identified and explains some adaptations and reproductive strategies.

 

Web References

Cook, J C. 2006. Integrated control of dodder (Cuscuta pentagona Englem.) using glyphosphate, ammonium sulfate, and the biological control agent Aternaria destruens simmons, sp. nov.  Doctoral dissertation.

Cook explains many aspects of dodder as she leads up to her experiment which focuses on the control of dodder.  She discusses many useful topics that introduce the reader to Cuscuta pentagona such as taxonomy, habitat range, and hosts. Cook goes on to describe the problems Cuscuta causes such as economic loss due to crop damage and fast spreading.  She talks about each chemical and its effect on dodder, then on biological controls, then explains her research objective.  Her research focuses on the control agent Aternaria destruens and its use in the control of dodder.  This article is a great source for many aspects of Cuscuta, and it is explained both generally and in depth.  Cook’s research seems sound and well-studied. 

 

Freckmann, R W. 2000. Family Cuscutaceae, Cuscuta pentagona Englem. Biology Department, University of Wisconsin-Stevens Point, Stevens Point, WI.

This webpage by and in tribute of Robert Freckmann, a long time professor of biology at the University of Wisconsin- Stevens Point, gives information about many plants.  A taxonomy is given to the family level.  Characteristics of each level are described.  There are hand drawn pictures to go along with the characteristics.  It is clear that much work and thought went into each description.  Cuscuta is placed in its own family Cuscutaceae, rather than with Convolvulaceae.  However, that may have been accepted at the time, and it is pointed out that Cuscutaceae is often synonymous with Convolvulaceae.  There is a segment on Cuscuta pentagona specifically focusing on its role in Wisconsin.  This resource will be helpful for defining characteristics of Cuscuta pentagona and for basic information.

 

Ombrello, T.  Dodder.  Biology Department, Union County College, Cranford, NJ.  

The entries found on this website feature a plant from the Union County College greenhouse every so often.  Information about that plant is posted.  Cuscuta is featured on this site.  Many common names of Cuscuta are given as well as background information.  The common names will be useful to relate the plant to more people as they may know it.  The time scheme of dodder from seed to adult to reproduction is spelled out clearly as it is seen in New Jersey.  The time frame will be a helpful resource that ties together much of the other information I’ve found.  The information seems reliable and well studied before writing the website.

UniProt. 2002. Cuscuta pentagona (fiveangled dodder).  

This site is for reference as to the classification of Cuscuta pentagona.  The taxonomy is very specifically laid out for each level and sublevel.  There are other useful websites linked to this page that have pictures and information about Cuscuta pentagona.  This is useful as a cross reference when used along with other sources.  This website is home for an organization that maps protein sequencing.  The taxonomy follows this purpose quite closely.

USDA, NRCS. 2012. Cuscuta pentagona Englem. five angled dodder. The PLANTS Database (http://plants.usda.gov). National Plant Data Team, Greensboro, NC 27401-4901 USA. 

This profile of Cuscuta pentagona by the USDA gives general background information about this plant.  A map with distribution is shown, along with Cuscuta pentagona’s status in certain states and areas.  For example, Cuscuta pentagona is considered a noxious weed in many states, but is considered endangered in two as well.  The phylogeny for Cuscuta pentagona is given with abbreviated explanations.  The distribution map is valuable for determining the habitat of Cuscuta pentagona.  This website is trustworthy as the NCRS database should be up to date and correct.

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