Metabolite mobilization in the stem galls of Parthenium hysterophorus induced by Epiblema strenuana inferred from the signatures of isotopic carbon and nitrogen and concentrations of total non-structural carbohydrates

Parthenium hysterophorus L. (Asteraceae) is a weed of national significance in Australia. Among the several arthropod agents introduced into Australia to control populations of P. hysterophorus biologically, Epiblema strenuana Walker (Lepidoptera: Tortricidae) is the most widespread and abundant agent. By intercepting the normal transport mechanisms of P. hysterophorus, the larvae of E. strenuana drain nutrients, other metabolic products, and energy, and place the host plant under intense metabolic stress. In this study, determinations of total non-structural carbohydrates (TNC) levels and carbon and nitrogen isotope ratios of fixed products in different parts of the plant tissue, including the gall, have been made to establish the function of gall as a sink for the nutrients. Values of δ13C and δ15N in galls were significantly different than those in proximal and distal stems, whereas the TNC levels were insignificant, when measured in the total population of P. hysterophorus, regardless of plant age. However, carbon, nitrogen, and TNC signatures presented significant results, when assayed in different developmental stages of P. hysterophorus. Carbon isotope ratios in galls were consistently more negative than those from the compared plant organs. Nitrogen isotope ratios in galls, on the contrary, were either similar to or less negative than the compared plant organs, especially within a single host-plant stage population (i.e., either rosette, preflowering, or flowering stage). TNC levels varied within compared plant populations. The stem distal to the gall functioned more efficiently as a nodal channel than the stem proximal to the gall, especially in the translocation of nitrogenous nutrients. Our findings indicate that the gall induced by E. strenuana functions as a sink for the assayed nutrients, although some variations have been observed in the patterns of nutrient mobilization. By creating a sink for the nutrients in the gall, E. strenuana is able to place the overall plant metabolism under stress, and this ability indicates E. strenuana has the necessary potential for use as a biological-control agent.

Recruitment sources of brown trout identified by otolith trace element signatures.

This study examined whether element: Ca ratios within the otoliths of juvenile brown trout could provide accurate trace element signatures for specific natal tributaries, and attempted to match these to trace element natal signatures found within the otoliths of adult trout caught in the main stem rivers of the same catchment. The trace element signatures of juvenile trout otoliths were analysed from a sample of eight tributaries representing the main sub-catchments of the Motueka River catchment, New Zealand. Trace element signatures were determined using laser ablation inductively coupled plasma mass spectrometry, and differentiated using linear discriminant function analysis with an overall cross-validated classification success of 96.8%. Temporal stability in element: Ca ratios was investigated by repeat collections of juvenile fish over two years. Natal signatures from 11 of 23 adult trout sampled from the catchment main stems were matched to one of the eight tributary signatures showing recruitment sources to be spread relatively evenly throughout the catchment. This study demonstrates the potential of using otolith trace element analysis to determine the natal origins of freshwater fish within a catchment.

Domestication and the storage starch biosynthesis pathway: Signatures of selection from a whole sorghum genome sequencing strategy

Next-generation sequencing of complete genomes has given researchers unprecedented levels of information to study the multifaceted evolutionary changes that have shaped elite plant germplasm. In conjunction with population genetic analytical techniques and detailed online databases, we can more accurately capture the effects of domestication on entire biological pathways of agronomic importance. In this study, we explore the genetic diversity and signatures of selection in all predicted gene models of the storage starch synthesis pathway of Sorghum bicolor, utilizing a diversity panel containing lines categorized as either ‘Landraces’ or ‘Wild and Weedy’ genotypes. Amongst a total of 114 genes involved in starch synthesis, 71 had at least a single signal of purifying selection and 62 a signal of balancing selection and others a mix of both. This included key genes such as STARCH PHOSPHORYLASE 2 (SbPHO2, under balancing selection), PULLULANASE (SbPUL, under balancing selection) and ADP-glucose pyrophosphorylases (SHRUNKEN2, SbSH2 under purifying selection). Effectively, many genes within the primary starch synthesis pathway had a clear reduction in nucleotide diversity between the Landraces and wild and weedy lines indicating that the ancestral effects of domestication are still clearly identifiable. There was evidence of the positional rate variation within the well-characterized primary starch synthesis pathway of sorghum, particularly in the Landraces, whereby low evolutionary rates upstream and high rates downstream in the metabolic pathway were expected. This observation did not extend to the wild and weedy lines or the minor starch synthesis pathways.

Domestication and the storage starch biosynthesis pathway: signatures of selection from a whole sorghum genome sequencing strategy

Next-generation sequencing of complete genomes has given researchers unprecedented levels of information to study the multifaceted evolutionary changes that have shaped elite plant germplasm. In conjunction with population genetic analytical techniques and detailed online databases, we can more accurately capture the effects of domestication on entire biological pathways of agronomic importance. In this study, we explore the genetic diversity and signatures of selection in all predicted gene models of the storage starch synthesis pathway of Sorghum bicolor, utilizing a diversity panel containing lines categorized as either ‘Landraces’ or ‘Wild and Weedy’ genotypes. Amongst a total of 114 genes involved in starch synthesis, 71 had at least a single signal of purifying selection and 62 a signal of balancing selection and others a mix of both. This included key genes such as STARCH PHOSPHORYLASE 2 (SbPHO2, under balancing selection), PULLULANASE (SbPUL, under balancing selection) and ADP-glucose pyrophosphorylases (SHRUNKEN2, SbSH2 under purifying selection). Effectively, many genes within the primary starch synthesis pathway had a clear reduction in nucleotide diversity between the Landraces and wild and weedy lines indicating that the ancestral effects of domestication are still clearly identifiable. There was evidence of the positional rate variation within the well-characterized primary starch synthesis pathway of sorghum, particularly in the Landraces, whereby low evolutionary rates upstream and high rates downstream in the metabolic pathway were expected. This observation did not extend to the wild and weedy lines or the minor starch synthesis pathways.

Standardising bull breeding soundness evaluations and reporting in Australia

There is substantial variation in bull breeding soundness evaluation procedures and reports in Australia; the situation is compounded by difficulties in interpretation and the validity of many reports. In an effort to overcome this, the scientific literature was reviewed [Fordyce G. In: Fordyce G, editor. Bull fertility: selection and management in Australia. Eight Mile Plains, Australia: Australian Cattle Vets; 2002] and the needs of stakeholders were considered in preparing a manual, Evaluating and Reporting Bull Fertility [Entwistle KW, Fordyce G. Evaluating and reporting bull fertility. Eight Mile Plains, Australia: Australian Cattle Vets; 2003.] that outlined standards for assessing and reporting bull breeding soundness. A new recording and reporting system, called Bull Reporter, is based on standards from this manual and groups bull fertility traits into five summary categories: Scrotum, Physical, Crush-side Semen, Sperm Morphology, and Serving. The client will generally select which categories they wish to have included in the evaluation to suit their specific purposes. While there is adequate room for comments, the veterinarian is not required to make an overall judgment of whether the bull has normal capacity to sire calves under natural mating management, but ensures the standards for each selected category are met. Professional, standardised, easy-to-read reports are produced either electronically [Entwistle KW, Fordyce G. Evaluating and reporting bull fertility. Eight Mile Plains, Australia: Australian Cattle Vets; 2003.] or manually. A bull owner or their agent signs the certificate to affirm that bulls have not undergone procedures to rectify faults which may have otherwise caused them to fail the standards. An accreditation system for assessing sperm morphology was established because of its demonstrated relationship with pregnancy rates and because of the difficulties in achieving consistent and accurate assessments among laboratories. It is considered that Bull Reporter is applicable to beef and dairy bulls across all levels of management, genotypes and environments throughout Australia, with substantial potential for application elsewhere in the world.

Cynodon dactylon, Green Couch, Turfgrass, Bermuda Grass 'Hatfield'

Low-growing plant with dark green foliage selected in 1983 from a population of green couch plants found in Gympie, Qld. Breeder: Graham Hatfield, Gympie, Qld. Application No. 2002/304. Australian PBR Certificate Number 2565, Granted 20 August 2004.

Cynodon dactylon Green Couch Grass, Bermuda Grass 'JT1'

Spontaneous mutation or chance seedling: discovered in the mid-1990s as a superior plant growing in a commercial field of “Common” Cynodon dactylon on Jimboomba Turf Company’s farm at Jimboomba in south-east Queensland. Selection criteria: vigorous lateral spread, high shoot density and turf quality, low inflorescence numbers, and darker green colour. In 1999 after observing the superior turf performance of this mutant plant as a small patch within a much larger paddock of “Common”, vegetative material was taken and propagated in clean ground elsewhere on the farm for multiplication and further trials in a variety of turf situations in south-east Queensland. Propagation: vegetative. Breeder: Lynn Davidson, Jimboomba, QLD. PBR Certificate Number 2640, Application Number 2002/282, granted 24 February 2005.

Cynodon transvaalensis x Cynodon dactylon Hybrid Green Couch Grass, Hybrid Bermuda Grass 'MS-Supreme'

Ploidy: triploid interspecific hybrid (3n = 27 chromosomes). Plant: habit prostrate, creeping, type mat-forming, height very short, longevity perennial, spreading laterally by stolons and rhizomes. Stolon: compound nodes with up to 3 leaves, internode length very short, internode thickness very thin, colour grey-brown (RHS N199A) when exposed to sunlight. Culms: length very short. Leaf blade: shape linear-triangular, length short, width narrow, colour dark green (RHS 137B). Ligule: dense row of short white hairs. Inflorescence: digitate with 3(-4) very short spicate racemes, peduncle very short. (All RHS colour chart numbers refer to 2001 edition.) PBR Certificate Number 2641, Application Number 2002/305, granted 24 February 2005.

Zoysia japonica, Zoysia Grass 'Palisades'

Open-pollination: originated as a chance seedling from Z44 (maternal clonal parent), obtained from Beltsville MD in 1981, with an unknown pollen source from a zoysia grass germplasm field nursery at the Texas Agricultural Experiment Station in Dallas. ‘Palisades’ was selected over the parent Z44 on the basis of its lower tendency to produce thatch, its excellent lateral growth habit and its superior mowing qualities. ‘Palisades’ has been vegetatively propagated, and is uniform in growth expression. No seedling establishment from ‘Palisades’ has been noticed in either greenhouse or field studies. Selection criteria: rapid regrowth and spread by, and/or from, stolons and rhizomes; turf colour and density; tolerance to low mowing; winter hardiness; shade tolerance; low water use requirements. Propagation: vegetative. Breeder: Milton C. Engelke, Dallas, USA. PBR Certificate Number 2594, Application Number 2001/199, granted 26 October 2004.

Cynodon transvaalensis x Cynodon dactylon, Hybrid Green Couch Grass, Hybrid Bermuda Grass 'TL2'

Spontaneous mutation: In 1996, vegetative material (later designated ‘TL2’) taken from a disease resistant mutant plant on the fifteenth green at Novotel Palm Cove resort course near Cairns was included an on-going program of selection and testing of promising ‘Tifgreen’ mutants by Tropical Lawns Pty Ltd. Selection criteria: healthy vigorous growth during the tropical wet season, dense fine-textured appearance under close mowing, and dark green leaves. In subsequent trials, ‘TL2’ was identified as the outstanding plant among selections of mutant ‘Tifgreen’ genotypes from other north Queensland sites in terms of colour, texture and density for greens use. Propagation: vegetative. Breeder: Terry Anderlini, Gordonvale, QLD. PBR Certificate Number 2639, Application Number 2002/268, granted 24 February 2005.

Cynodon dactylon, Green Couch Grass 'TL1'

Chance seedling: observed in about 1989 as a distinctly coarser textured, densely matting, darker green mutant bermuda grass plant growing among the hybrid ‘Tifgreen’ on the eighth green at the Townsville Golf Course. Although ‘TL1’ was selected from a sward of the hybrid Bermuda grass ‘Tifgreen’, its inflorescence structure (4, not 3, racemes per inflorescence), agronomic attributes (e.g. its tolerance to certain herbicides), and its DNA profile are consistent with a chance seedling of Cynodon dactylon rather than a mutant plant of hybrid (C. dactylon x transvaalensis) origin. Selection criteria: exceptionally short stolon internodes resulting in an extremely tight knit stolon mat under close (c. 5-6 mm) but not very close (c. 3-4 mm) mowing; very deep, strong rhizome system; very dark green colour; tolerates shade better than other Australian bermuda grass varieties of common knowledge (except for ‘Plateau’A); and remains low growing under heavy tropical cloud cover even after 6-8 months. Designated ‘TL1’ by Tropical Lawns Pty Ltd and trialed successfully during the late 1990s and early 2000s in high wear situations (e.g. golf tees) in north Queensland. Propagation: vegetative. Breeder: Barry McDonagh, Townsville, QLD. PBR Certificate Number 2638, Application Number 2002/267, granted 24 February 2005.

Cynodon dactylon, Green Couch Grass 'Oz-E-Green'

Spontaneous mutation or chance seedling: discovered in 2001 as a superior plant growing among “Common” green couch on the breeder’s turf farm at Berries Road, Childers. A selected piece of sod was removed and broken into vegetative sprigs to propagate a larger area of this variety elsewhere on the breeder’s property. The original plant has now been multiplied vegetatively three times without showing any discernible off types. Selection criteria: dense prostrate habit and limited inflorescence production (giving a low mowing requirement), high turf quality, dark green colour. Propagation: vegetative. Breeder: Robert William Morrow, Childers, QLD. PBR Certificate Number 2844, Application Number 2004/035, granted 22 August 2005.

Stenotaphrum secundatum, Buffalo Grass 'Sir James'

Spontaneous mutation: discovered in February 2001 as a superior plant growing among “Common” buffalo grass growing on the breeder’s property at Saltash in the Hunter Valley (NSW). The selected material has smaller (finer) leaves and showed better growth and colour than the parent variety with minimal inputs (water, fertiliser) under stressful climatic conditions. Subsequently, it also showed better leaf colour retention than the parent variety during winter. A vegetative plug taken from the original plant has now undergone four subsequent vegetative divisions to expand the original material for performance trials in NSW and Queensland without showing any discernible off types. Main selection criteria: winter colour retention, small leaves, low fertiliser requirement. Propagation: vegetative. Breeder: Brent Redman, Maitland North, NSW. PBR Certificate Number 2715, Application Number 2002/283, granted 18 March 2005.

Cynodon dactylon, Green Couch Grass, Bermuda Grass 'Grand Prix'

‘Grand Prix’ is a selection from a cross between ‘Wintergreen’ and ‘Couch 5’ (also designated C5). ‘Couch 5’ was a selection from an earlier series of crosses by the breeder between ‘Wintergreen’ and a number of Cynodon dactylon accessions, which were collected by the breeder from the Mornington Peninsula area of Victoria between 1986 and 1990. C5 was an experimental breeding line, and was not subsequently reserved as vegetative germplasm. Living material of C5 is no longer in existence. Following the crossing of ‘Couch 5’ and ‘Wintergreen’ in 1998, the resultant seed was germinated on moist blotting paper. Individual seedlings, a total of 150 in number, were planted into 150mm pots and these plants observed during 1998 and 1999. During the summer of 1999-2000, the majority of the seedling plants were culled on the basis of their shoot density, leaf texture, internode length, and colour. In the spring of 2000, the remaining 20 potted seedlings were planted individually into 4m2 plots at the Evergreen Turf farm at Pakenham (Victoria), and allowed to expand fully across these plots. The final selection of Seedling 12 (later designated DN12) in late 2002 was based on shoot density, leaf colour, turf quality, and reduced thatch accumulation as expressed in these plots. Propagation: the original plant has been multiplied through four (4) vegetative expansions prior to PBR application without showing any discernible off types. Breeder: David Nickson, Frankston, VIC. PBR Certificate Number 3133, Application Number 2005/291, granted 12 September 2006.

Cynodon dactylon, Green Couch Grass, Bermuda Grass 'Winter Gem'

‘Winter Gem’ is a selection from a cross between ‘Wintergreen’ and Couch 5 (also designated C5). Couch 5 was a selection from an earlier series of crosses by the breeder between ‘Wintergreen’ and a number of Cynodon dactylon accessions, which were collected by the breeder from the Mornington Peninsula area of Victoria between 1986 and 1990. C5 was an experimental breeding line, and was not subsequently reserved as vegetative germplasm. Living material of C5 is no longer in existence. Following the crossing of Couch 5 and ‘Wintergreen’ in 1998, the resultant seed was germinated on moist blotting paper. Individual seedlings, a total of 150 in number, were planted into 150mm pots and these plants observed during 1998 and 1999. During the summer of 1999-2000, the majority of the seedling plants were culled on the basis of their shoot density, leaf texture, internode length, and colour. In the spring of 2000, the remaining 20 potted seedlings were planted individually into 4m2 plots at the Evergreen Turf farm at Pakenham (Victoria), and allowed to expand fully across these plots. The final selection of Seedling 9 (later designated DN9) in late 2002 was based on shoot density, leaf texture, and retention of winter colour as expressed in these plots. Propagation: The original plant had been multiplied through four (4) vegetative expansions prior to PBR application without showing any discernible off types. Breeder: David Nickson, Frankston, VIC. PBR Certificate Number 3132, Application Number 2005/290, granted 11 September 2006.