title: Resistance to African black beetle (Heteronychus arator) in perennial ryegrass (Lolium perenne L.) infected with AR1 endophyte

authors: Ross, Kathryn Mary

subjects: Epichloë festucae var. lolii

abstract: The insect pest, African black beetle (Heteronychus arator (Fabricus, 1775)) is of considerable economic cost to the New Zealand agricultural industry, in regions where the insect is established and regular outbreaks are now occurring. Selection for Epichloë festucae var. lolii (Latch, M.J. Chr. & Samuels) C. W. Bacon & Schardl, stat. nov. et comb. nov. endophyte-perennial ryegrass (Lolium perenne L.) associations which do not cause toxicity to livestock and with strong resistance to African black beetle (H. arator), would be of significant value to farmers in regions where this pest is a problem.
Epichloë festucae var. lolii strain AR1 endophyte does not produce ergovaline, the alkaloid known to deter African black beetle (H. arator), yet pastures infected with this endophyte have moderate resistance to adult African black beetle (H. arator). Research into AR1 is of importance, as to date there have been no reports of toxicity in livestock brought about by consumption of from AR1-infected pastures and in the absence of African black beetle (H. arator) this ‘novel’ endophyte can provide highly productive pastures.
AR1 endophyte produces secondary metabolites that are simple indole diterpenes, including paxilline and paxilline-like compounds. The numerous paxilline-like compounds produced by AR1 are detected by a paxilline ELISA (enzyme linked immunosorbant assay) and quantified collectively as paxilline immunoreactive equivalents. Earlier work suggested that these paxilline-like compounds could be the bioactive, or linked-marker associated with the bioactive compound(s), that provide some resistance to adult African black beetle (H. arator) feeding.
The overall aim of this research was to determine if increased concentration of paxilline immunoreactivity was associated with a reduction in feeding damage using a series of adult African black beetle (H. arator) feeding trials on closely related AR1-infected perennial ryegrasses (L. perenne).
A negative relationship was established between feeding damage from adult African black beetle (H. arator) and plant pseudostem paxilline immunoreactivity in AR1-infected perennial ryegrass (L. perenne) post exposure to beetles. However, it was not a simple relationship being complicated by: i) paxilline immunoreactivity ￼not reflecting endophyte concentrations; ii) the influence of cultivar on the expression levels of paxilline immunoreactivity; iii) the effect of African black beetle (H. arator) presence on expression levels of paxilline immunoreactivity; and iv) the paxilline ELISA quantifying the complete complex of paxilline-like compounds and not simply those that are bioactive.
The highest concentrations of paxilline immunoreactivity were found in plant undamaged pseudostem and were not strongly correlated with the lower concentrations found in herbage. Therefore undamaged pseudostem is recommended as the section sampled if the entire plant pseudostem was not available. Low levels of feeding from adult African black beetle (H. arator) accentuated plant tiller production. However, the negative effects of high feeding pressure still affected plants four weeks post-exposure to beetles, with reduced paxilline immunoreactivity production and plant tiller numbers. Adult African black beetle (H. arator) were able to compensate the deterrent effects of AR1 once an endophyte-free food source was available.
Results from this research contribute towards further understanding the bioactivity of AR1 endophyte against adult African black beetle (H. arator) and will underpin further research into the chemical basis for this resistance. The paxilline ELISA could potentially be used for screening E. festucae endophyte ryegrass associations that produce unknown compounds which deter African black beetle (H. arator) and which do not cause toxicity to livestock.

text: Resistance to African black beetle (Heteronychus arator) in perennial ryegrass (Lolium perenne L.) infected with AR1 endophyte The insect pest, African black beetle (Heteronychus arator (Fabricus, 1775)) is of considerable economic cost to the New Zealand agricultural industry, in regions where the insect is established and regular outbreaks are now occurring. Selection for Epichloë festucae var. lolii (Latch, M.J. Chr. & Samuels) C. W. Bacon & Schardl, stat. nov. et comb. nov. endophyte-perennial ryegrass (Lolium perenne L.) associations which do not cause toxicity to livestock and with strong resistance to African black beetle (H. arator), would be of significant value to farmers in regions where this pest is a problem.
Epichloë festucae var. lolii strain AR1 endophyte does not produce ergovaline, the alkaloid known to deter African black beetle (H. arator), yet pastures infected with this endophyte have moderate resistance to adult African black beetle (H. arator). Research into AR1 is of importance, as to date there have been no reports of toxicity in livestock brought about by consumption of from AR1-infected pastures and in the absence of African black beetle (H. arator) this ‘novel’ endophyte can provide highly productive pastures.
AR1 endophyte produces secondary metabolites that are simple indole diterpenes, including paxilline and paxilline-like compounds. The numerous paxilline-like compounds produced by AR1 are detected by a paxilline ELISA (enzyme linked immunosorbant assay) and quantified collectively as paxilline immunoreactive equivalents. Earlier work suggested that these paxilline-like compounds could be the bioactive, or linked-marker associated with the bioactive compound(s), that provide some resistance to adult African black beetle (H. arator) feeding.
The overall aim of this research was to determine if increased concentration of paxilline immunoreactivity was associated with a reduction in feeding damage using a series of adult African black beetle (H. arator) feeding trials on closely related AR1-infected perennial ryegrasses (L. perenne).
A negative relationship was established between feeding damage from adult African black beetle (H. arator) and plant pseudostem paxilline immunoreactivity in AR1-infected perennial ryegrass (L. perenne) post exposure to beetles. However, it was not a simple relationship being complicated by: i) paxilline immunoreactivity ￼not reflecting endophyte concentrations; ii) the influence of cultivar on the expression levels of paxilline immunoreactivity; iii) the effect of African black beetle (H. arator) presence on expression levels of paxilline immunoreactivity; and iv) the paxilline ELISA quantifying the complete complex of paxilline-like compounds and not simply those that are bioactive.
The highest concentrations of paxilline immunoreactivity were found in plant undamaged pseudostem and were not strongly correlated with the lower concentrations found in herbage. Therefore undamaged pseudostem is recommended as the section sampled if the entire plant pseudostem was not available. Low levels of feeding from adult African black beetle (H. arator) accentuated plant tiller production. However, the negative effects of high feeding pressure still affected plants four weeks post-exposure to beetles, with reduced paxilline immunoreactivity production and plant tiller numbers. Adult African black beetle (H. arator) were able to compensate the deterrent effects of AR1 once an endophyte-free food source was available.
Results from this research contribute towards further understanding the bioactivity of AR1 endophyte against adult African black beetle (H. arator) and will underpin further research into the chemical basis for this resistance. The paxilline ELISA could potentially be used for screening E. festucae endophyte ryegrass associations that produce unknown compounds which deter African black beetle (H. arator) and which do not cause toxicity to livestock.

year: 2016

title: Anisotropic scaling of magnetohydrodynamic turbulence

authors: Horbury, Timothy S.

subjects: mathematics

abstract: We present a quantitative estimate of the anisotropic power and scaling of magnetic field fluctuations in inertial range magnetohydrodynamic turbulence, using a novel wavelet technique applied to spacecraft measurements in the solar wind. We show for the first time that, when the local magnetic field direction is parallel to the flow, the spacecraft-frame spectrum has a spectral index near 2. This can be interpreted as the signature of a population of fluctuations in field-parallel wavenumbers with a k║-2 spectrum but is also consistent with the presence of a "critical balance" style turbulent cascade. We also find, in common with previous studies, that most of the power is contained in wavevectors at large angles to the local magnetic field and that this component of the turbulence has a spectral index of 5/3.

text: Anisotropic scaling of magnetohydrodynamic turbulence We present a quantitative estimate of the anisotropic power and scaling of magnetic field fluctuations in inertial range magnetohydrodynamic turbulence, using a novel wavelet technique applied to spacecraft measurements in the solar wind. We show for the first time that, when the local magnetic field direction is parallel to the flow, the spacecraft-frame spectrum has a spectral index near 2. This can be interpreted as the signature of a population of fluctuations in field-parallel wavenumbers with a k║-2 spectrum but is also consistent with the presence of a "critical balance" style turbulent cascade. We also find, in common with previous studies, that most of the power is contained in wavevectors at large angles to the local magnetic field and that this component of the turbulence has a spectral index of 5/3.

year: 2008

title: Hone Werahiko: the discoverer of gold at Te Aroha

authors: Hart, Philip

abstract: Originally Hone Kahukahu, when he was living at Ohinemutu in the 1860s he became known as Hone Werahiko, an Arawa name he retained for the rest of his life. His father, a member of Ngati Kahungungu, had been captured by Arawa; his mother was a Waikato. A widow living at Maketu chose him as her second husband because he was ‘a good looking fellow & understood English’. 
In the late 1860s and much of the 1870s, he prospected in Hauraki and even in the King Country, and worked underground in a Thames mine, the only Maori known to have done so. But in the early 1870s he gave up mining to be a pioneer publican and storekeeper at Ohinemutu, at Rotorua. He acquired land and property there, but after his wife died he returned to prospecting full-time. 
Werahiko’s first investigation of Te Aroha was in 1877, when he was ordered off by the local hapu. He returned in 1880 as the head of a prospecting party subsidized by the government. After finding gold, he was granted the Prospectors’ Claim and, in due course, a reward, and for a time supervised its development. Investing in other claims, he traded in shares. When his discovery turned out to be a duffer, he explored other parts of the mountain, first having high hopes for the Tui portion but then, after four months of exploring over winter with the support of three other Maori, he announced the discovery of his New Find at Waiorongomai. Once again he acquired partners, mostly Paheka, and traded in shares, and for some time supervised the opening up of his new find.
Later, he was invited to prospect the King Country, but this did not eventuate. His last involvement in mining was at Karangahake. Because of the hardships of his prospecting at Te Aroha, he died at an early age, leaving a young second wife. His memory lived on, amongst Pakeha miners in particular, because he had the rare distinction for a prospector of being regarded as totally honest, and he was admired for succeeding when so many others had failed.

[Note: Especially when he first came to public attention, many Pakeha struggled with Hone Werahiko’s name, which was recorded in a variety of incorrect forms, the worst example being Hoani Whaekareka.  Even the warden at first gave his name as Hone Wharekino.  Many Pakeha found it simpler to refer to him as ‘Johnny the Maori’.  In this paper, his name is given correctly throughout.]

text: Hone Werahiko: the discoverer of gold at Te Aroha Originally Hone Kahukahu, when he was living at Ohinemutu in the 1860s he became known as Hone Werahiko, an Arawa name he retained for the rest of his life. His father, a member of Ngati Kahungungu, had been captured by Arawa; his mother was a Waikato. A widow living at Maketu chose him as her second husband because he was ‘a good looking fellow & understood English’. 
In the late 1860s and much of the 1870s, he prospected in Hauraki and even in the King Country, and worked underground in a Thames mine, the only Maori known to have done so. But in the early 1870s he gave up mining to be a pioneer publican and storekeeper at Ohinemutu, at Rotorua. He acquired land and property there, but after his wife died he returned to prospecting full-time. 
Werahiko’s first investigation of Te Aroha was in 1877, when he was ordered off by the local hapu. He returned in 1880 as the head of a prospecting party subsidized by the government. After finding gold, he was granted the Prospectors’ Claim and, in due course, a reward, and for a time supervised its development. Investing in other claims, he traded in shares. When his discovery turned out to be a duffer, he explored other parts of the mountain, first having high hopes for the Tui portion but then, after four months of exploring over winter with the support of three other Maori, he announced the discovery of his New Find at Waiorongomai. Once again he acquired partners, mostly Paheka, and traded in shares, and for some time supervised the opening up of his new find.
Later, he was invited to prospect the King Country, but this did not eventuate. His last involvement in mining was at Karangahake. Because of the hardships of his prospecting at Te Aroha, he died at an early age, leaving a young second wife. His memory lived on, amongst Pakeha miners in particular, because he had the rare distinction for a prospector of being regarded as totally honest, and he was admired for succeeding when so many others had failed.

[Note: Especially when he first came to public attention, many Pakeha struggled with Hone Werahiko’s name, which was recorded in a variety of incorrect forms, the worst example being Hoani Whaekareka.  Even the warden at first gave his name as Hone Wharekino.  Many Pakeha found it simpler to refer to him as ‘Johnny the Maori’.  In this paper, his name is given correctly throughout.]

year: 2016