Genetic Polymorphisms Of Opuntia Fragilis Biology Essay

The Cactaceae are an exciting and disputing group of workss because of their varied morphology and succulency, their flamboyant flowers, their versions to the environment, and their generative schemes. The Cactaceae household are New World workss, arising in the North, Central, and South American continents, including the West Indies Islands ( in the Caribbean ) and the Galapagos Islands. There are four subfamilies: Pereskioideae, Maihuenioideae, Opuntioideae, and Cactoideae.

Opuntioideae have a important diverseness of signifier and home ground and are widely distributed throughout the New World ( Griffith andA Porter, 2009 ) .Designation of species within the subfamily Opuntioideae can be hard, in portion because of widespread phenotypic malleability, interspecies hybridisation, polyploidy, and apomixis ( clonal seeds and stems ) , which play of import evolutionary functions, peculiarly in Cylindropuntia and Opuntia ( Pinkava, 2002 ) . Opuntia is a big genus that contains many of the tablet cacti or bristly pear cacti ( Figure 1 ) . Opuntia species have been ill studied ecologically and taxonomically in the Midwest United States.

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Opuntia fragilisA ( Nuttall ) Haworth was foremost described by Thomas Nuttall in 1819. He named it Cactus fragilis, and Haworth subsequently moved it to the Opuntia genus: Opuntia fragilis. The specific name ‘fragilis ‘ refers to the easiness with which the terminus articulation is detached, an version for nonsexual reproduction and dispersion ( Ribbens, 2007 ) .O.

fragilisA is found farther north than any other cactus species in the universe, turning in northern Alberta merely 4oA South of the Arctic Circle ( Taylor, 2005 ) . O. fragilis is widely distributed across North America ( Figure 2 ) . It occurs from Ontario South to Texas and west to British Columbia, Washington, Oregon, and California ( Taylor, 2005 ) . O. fragilisA is scattered throughout the upper Midwest, where it is rare in Ontario, Iowa, Illinois, and Michigan and instead uncommon in Minnesota and Wisconsin.The Flora of North America distribution map of Opuntia fragilisFigure 2: Distribution of Opuntia fragilis in North America.Accessed October 21, 2009.

Image Beginning: www.EFloras.orgO. fragilis prefers home grounds with open bedrocks or sandy and gravelly dirts of prairie grasslands and has besides been located in countries of light shadiness at borders of forested coulees and grasslands ( Cota, 2002 ) . In bristly pears, each tablet, in its first twelvemonth merely, produces areoles with delimiting conelike foliages.

These foliages are normally dropped after a few hebdomads. The areole besides produces foliages modified into spinal columns of two sorts — lasting spinal columns with their bases embedded in cork and little, biting, easy dislodged glochids. The bristly pears thrive in arid, shallow and well-drained dirts, but besides on overgrazed sites.The cladophylls are flattened into tablets ; the fruits are berries, and in many species comestible. Opuntias are biologically complex desert plants.

Opuntias flourish in desert-like home grounds due to legion xerophytic versions. These include midst, waxy cuticles that cut down the sum of H2O lost through transpiration and modified foliages, and bud graduated tables in the signifier of spinal columns and glochids that lessening works surface areaproducing low transpiration rates to cut down H2O loss. Malic acid or isocitric acid are accumulated in the vacuoles of photosynthetic cells at dark and metabolized to let go of C dioxide during the twenty-four hours. This type of photosynthesis is referred to as Crassulacean acid metamorphosis or more merely, CAM photosynthesis ( Majure and Ervin, 2007 ) .The extremely spread systematic distribution of CAM photosynthesis, which occurs in 33 households and an estimated 16,000 species of vascular workss, suggests it has arisen on multiple occasions. In households such as the Agavaceae, Cactaceae, and Didiereaceae, about all species have the capacity for CAM photosynthesis and therefore exhibit the presumed apomorphic character-state ( Crayn et al. , 2004 ) . Cacti have helped evolutionary life scientists and ecologists understand CAM photosynthesis ( Crassulacean acid metamorphosis ) and succulency ( Mihalte et al.

, 2008 ) . During the dark, they open pores and CO2A enters the foliage cells where it combines with PEP ( phosphoenolpyruvate ) to organize 4-carbon organic acids ( malic and isocitric acids ) . During the twenty-four hours, their pores are closed ; nevertheless they still carry on photosynthesis with the modesty supply of CO2A that was trapped during the dark when the pore were unfastened and C dioxide gas is converted into simple sugars. Therefore, there is an addition in water-use efficiency because the pore unfastened at dark ; CO2A is fixed when the air temperatures areA lower and the comparative humidness is higher, cut downing H2O loss ( Hernandez-Gonzales and Villarreal, 2007 ) .Flowers in the Cactaceae are normally perfect, incorporating both functional pistils and stamens ( Figure 3 ) . Such flowers can either outcross with other persons or be self-fertile and pollinate themselves ( Rebman and Pinkava, 2001 ) . Many bristly pears are seemingly self-incompatible ( Ribbens and Anderson, 2008 ) .

O. fragilis surely is, at least in Illinois ( Ribbens and Anderson, 2008 ) . Asexual reproduction is doubtless responsible for the success and spread of this population on the border of the scope of the species ( Ribbens and Anderson, 2008 ) . Asexual reproduction is a common happening for many Opuntias.

The most prevailing type of cloning in this group is vegetive extension by root or cladophyll withdrawal. The terminal root sections of some species ( e.g.

, Cylindropuntia leptocaulis ( DeCondolle ) Knuth, O. fragilis, and O. pubescens Wendland ) detach with easiness from the parent works and readily take root, making clonal persons ( Rebman and Pinkava, 2001 ) .

Figure 3: Opuntia fragilis flower.Image from web site: hypertext transfer protocol: // flesh of O. fragilis was used by the Okanagan-Colville Native Americans to handle skin infections and was eaten for its diuretic belongingss.

The roots were used as nutrient by the Okanagan-Colville and Shuswap folks ( Cota, 2002 ) .It is good known to everyone familiar with handling of cactus cladophylls ( known in Mexico as nopalitos ) or prickly-pear fruit in the kitchen, that when cut, both secrete a characteristic sludge. The chief component of this secreted fluid is polysaccharide mucilage ( Cardenas et al. , 1997 ) .

The mucilage obtained from cactus is normally described as water-soluble pectin-like polyose ( Cardenas et al. , 1997 ) . Mucilage production is common to many groups of workss.

The mechanism of secernment is seemingly the same in different works species ( Trachtenberg and Fahn, 1981 ) . Fresh tissue from cacti nowadayss big sums of polyphenolics and polyoses that co-precipitate with DNA and affect subsequent PCR elaboration ( Mihalte et al. , 2008 ) .

The ability of Cactaceae to retain H2O under such unfavourable climatic conditions is due in portion, at least, to the water-binding capacity of mucilage ( Mindt et al. , 1975 ) . The carbohydrate composing of mucilages from several Opuntia species has been good established by different chromatographic techniques. From his probes, Lauterbach ( 1889 ) concluded that there are two methods by which the mucilage is formed, one keeping true for Opuntia, and the other for the balance of the cactus groups.

In the Opuntia the mucilage arises in a cell incorporating a little crystal of some oxalate. This crystal seemed to excite the growing of the cell. Subsequently the karyon and crystal might look suspended on strands of cytol in the thick of the cell and mucilage would so get down to look in the fringe of the living substance ( Stewart, 1919 ) .The genus Opuntia consists of 200 species that are classified based on their morphological and physiological traits ( Helson et al, 2007 ) . The usage of molecular techniques has proven utile in understanding the genetic sciences of Opuntia. For illustration, Labra et Al. ( 2003 ) have suggested that O.

ficus-indica should be considered a domesticated signifier of O. megacantha based on molecular informations [ chloroplast simple sequence repetition ( cpSSR ) and amplified fragment length polymorphism ( AFLP ) ] , morphological traits and biogeographic distribution.Butterworth and Wallace ( 2005 ) investigated the evolutionary relationships in Pereskia and informal infrageneric groupings. In this survey, they isolated entire genomic Deoxyribonucleic acid utilizing a modified cell organ pellet method suited for gluey stuff ( Butterworth and Wallace, 2005 ) . With the aid of their molecular informations they found that Pereskia, by and large interpreted as the sister group to the remainder of Cactaceae, appears to be paraphyletic. In recent probes made by Butterworth and Edwards ( 2008 ) on Pereskia and the earliest divergencies in Cactaceae, they present a sum-up of the two old molecular ( DNA ) phyletic surveies of Pereskia ( Butterworth and Wallace 2005 ; Edwards and others 2005 ) with their analysis of combined DNA sequence informations used in those surveies ( Butterworth and Edwards, 2008 ) .A high-yielding micromethod for DNA extraction was established by utilizing merely little sums of a specialised tissue of O.

ficus-indica cladophylls to be used for genomic word picture. Besides, the RAPD analysis of this works stuff was performed by eight primers bespeaking familial uniformity of the stuff ( Arnholdt-schmitt et al. , 2001 ) . However, there are jobs associated with pull outing Deoxyribonucleic acid from cladophylls, leaves or dried roots since they have high degrees of polyoses, phenoplasts and other secondary metabolites ( Tel-Zur et al. , 1999 ) .Presence of these polyoses was indicated by the syrupy, glue like texture of all infusions at all phases of DNA isolation ( Tel-Zur et al. , 1999 ) .

The syrupy DNA solution was impure and unamplifiable in the polymerase concatenation reaction ( PCR ) due to suppression of Taq polymerase activity ( Fang et al. , 1992 ) . Though original CTAB method ( Doyle and Doyle, 1990 ; Reichardt and Rogers, 1994 ) was helpful in successfully pull outing and insulating Deoxyribonucleic acid from the cactus species Opuntia ficus-indica and Cereus peruvianus, it was unsuccessful in insulating Deoxyribonucleic acid from certain species of the genera ( Tel-Zur et al. , 1999 ) .In a survey made by Mondragon ( 2001b ) , he stated that alterations such as optimisation of sample size, incorporation of indissoluble polyvinylpyrrolidone, increased clip centrifugation and separation of the acid pill nucleic bath could cut down the job of the presence of mucilage in the sample, doing gelation of the sample doing it hard to centrifugation and separation of the DNA pellet ( Mondragon, 2001b ) .

To get the better of the mucilage job to an extent and obtain a extremely pure DNA, we used roots for extraction of the familial stuff. My survey examines the genetic sciences of O. fragilis by analysing ISSR polymorphisms in the Midwest United States. The chief aims of this undertaking are to analyse genetic sciences between and within populations for Illinois, Iowa, Michigan, Minnesota and Wisconsin.


Sampling:Forty root samples were harvested from Opuntia fragilis tablets that were collected from populations in Midwest ( Illinois, Iowa, Michigan, Minnesota, and Wisconsin ) .

Pads were floated in H2O until they produced roots. These roots were so preserved in Ethanol and stored for future usage. Genomic DNA samples isolated from the roots of these O. fragilis tablets were prepared by utilizing the CTAB-chloroform protocol ( Dr.

Alton, personal communicating ) .The CTAB ( Hexadecyltrimethylammoniumbromid ) is a cationic detergent that forms a complex with the Deoxyribonucleic acid. The CTAB-DNA composite is so separated from the cellular dust by trichloromethane. In this measure, we can detect two beds: a superior clear aqeous bed incorporating the Deoxyribonucleic acid and a denser inferior bed incorporating the trichloromethane and all other secondary constituents such as proteins, polyoses etc. After centrifugation, cellular dust can normally be observed at the interface. The purification by trichloromethane can be repeated several times. The topmost aqeous bed is transferred to a clean eppendoff and equal volume of isopropyl alcohol is added.

This CTAB-chloroform protocol was used to insulate genomic Deoxyribonucleic acid from roots of O. fragilis that would so be subjected to ISSR analysis from the works.The isopropyl alcohol is poured out go forthing behind the precipitate. After the precipitation, the Deoxyribonucleic acid molecule must be washed with ethyl alcohol.

The Deoxyribonucleic acid is so dissolved and stored in a tris/EDTA ( TE ) buffer.Amplification and Sequencing:Polymerase concatenation reaction ( PCR ) was performed for 10 samples in Applied Biosystems Step One plus Real Time PCR system. The Genomic Deoxyribonucleic acid from our samples was amplified utilizing three ISSR primers where ISSR stands for Inter simple sequence repetitions. The ISSR primers use microsatellite sequence stoping in an excess base to ground it to specific parts and were suggested by Dr.

Jeremy Fant. The ISSR primer sequences are listed below:Primer 1: AGA GAG AGA GAG AGA GTPrimer 2: ACA CAC ACA CAC ACA CCPrimer 3: ACA CAC ACA CAC ACA CGEach ISSR reaction was carried out in a entire volume of 5AµL, incorporating 5U/AµL Master Amp, and 0.5Aµl of Taqman polymerase, 1Aµl of genomic DNA. Initial denaturation was carried out for 10min at 95A°C, followed by 40 rhythms for 1 min at 95A°C, 1 min at 53.

5A°C for two primers and 1 min at 72A°C.Agarose cataphoresis in 1X TAE buffer was used to visualise the size of sets expected. Product lengths of 3 samples were analyzed on a 1.5 % agarose gel and visualized utilizing 0.5 Aµg/ml Ethidium Bromide discoloration.


I was non able to successfully execute PCR analysis on these samples.

I believe this is due to high polyose composings in the samples. Subsequent cataphoretic analysis showed a distinguishable set of high-molecular-weight DNA and a vilification of RNA ( Figure 4 ) . Isolation of good quality Deoxyribonucleic acid from O. fragilis is complicated by the presence of big sums of polysaccharide-based mucilage in its roots. Besides, the other possibilities of non acquiring DNA sets on the gel could be deficient measure or concentration of DNA loaded on the gel or the Deoxyribonucleic acid was degraded or the Deoxyribonucleic acid was electrophoresed off the gel and so electrophoresing the gel for less clip might hold been helpful.

Figure 4: Photograph of gel loaded with 6 Deoxyribonucleic acid samples.


The chief aim of this undertaking was to cover with the genetic sciences of Opuntia fragilis to analyse the ISSR polymorphisms in the Midwest United States. This was non achieved due to possibility of the polluting polyoses present in the genomic Deoxyribonucleic acid extracted from the roots of O. fragilis.For many old ages the function of mucilage in succulents was thought to be in H2O preservation ( Evans, 1932 ) . Sutton et Al. ( 1981 ) suggest that mucilage serves as a saccharide modesty in add-on to glucan. The biochemistry for this possible modesty function is soon unknown ( Holthe and Szarek, 1985 ) .

Despite the betterments in the extraction of DNA, legion protocols are limited to specific works groups ( Cota et al. , 2006 ) . It is true that extraction of Deoxyribonucleic acid from cacti can be more hard than from other workss because of their low outputs of DNA. Cacti, among other succulents, may frequently incorporate big sums of polysaccharide-based mucilage which can adhere H2O in extraction buffers, doing trouble in pipetting and centrifugation ( Griffith and Porter, 2003 ) .

They besides contain high sums of secondary metabolites which form indissoluble composites with nucleic acids during extraction. ( Guillemaut and Marechal, 1992 ) .Surveies of the molecular biological science of Opuntia fragilis are limited. The inclusion of molecular informations will be helpful to clear up categorization within the Opuntia genus.

The monophyly of the folk Cactaceae was tested utilizing rpl16 noncoding DNA sequence fluctuation informations which helped decide the intergeneric relationships in Cactaceae and besides the monophyly in antecedently proposed cacteae genera was assessed utilizing this molecular information ( Butterworth et al. , 2001 ) . In a survey conducted by Dr. Wang et Al. ( 1998 ) molecular analysis of RAPD marker forms demonstrated the utility of molecular markers in the categorization of Opuntia accessions. Their experiments besides indicated the feasibleness of a comprehensive attempt to find the relationships among Opuntia species utilizing molecular markers ( Wang et al. , 1998 ) .

High degrees of polymorphism in Galapagos bristly pear ( Opuntia ) cactus species were observed by developing 16 microsatellite markers and analyzing the population familial construction of Galapagos bristly pear ( Opuntia ) cactus species ( Helsen, 2007 ) . Amplified fragment length informations can be used to reply a broad scope of familial inquiries ( Mueller and Wolfenbarger, 1999 ) . With the aid of amplified fragment length technique, even little sums of genomicA Deoxyribonucleic acid can be used to produceA DNAA ” fingerprints ” that are extremely specific to particularA species. AFLPA can besides be used to determineA familial variationA across different populations ( Chial, 2008 ) . Therefore, Amplified fragment length technique generates the consequences in the signifier of big figure of fragments which gives us an estimation of fluctuation across the full genome. These big Numberss of fragments therefore gives a good general image of the degree of familial fluctuation of the O.

fragilis.However, DNA isolation in my survey was highly hard because of the presence of acidic polyoses and polyphenols. Therefore, I conclude that the interventions with the Deoxyribonucleic acid in my samples are due to the Opuntia polyose composings and non a contaminating artefact. Further betterment of theA extraction methodological analysis will let research workers to insulate good quality Deoxyribonucleic acid from roots of O.

fragilis and analyse the ISSR polymorphisms among species. DNA sequence-based phylogeneticA appraisals may bespeak that a genome wideA attack may give more utile fluctuation for the genusA Opuntia.


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