NEMATODE COMMUNITY STRUCTURE AS INFLUENCED BY LAND USE AND INTENSITY OF CULTIVATION

This study was conducted to determine the effect of land use and intensity of land cultivation on the nematode community structure. The land use types represented in the study sites were natural forest, plantation forest, tea, coffee, napier grass, agroforestry, fallow and annual crop cultivation dominated by maize intercropped with beans. Nematode diversity and abundance decreased with intensity of land cultivation, with the natural forest being regarded as the benchmark. The decrease in nematode diversity was assessed using Shannon, Simpson and species richness indices and was used to reflect the underlying changes in physical, chemical and biological properties of soil environment. The highest maturity indices for free-living and plant parasitic index were recorded in the natural forest and intensively cultivated land under annual crops (maize/beans), respectively. Plant parasitic nematodes were predominant in soils that were under agricultural production while saprofagic nematodes dominated the forested land as exemplified by the ratios of free-living to plant parasitic which were, 5.18 and 0.54 in the natural forest and annual crop production systems respectively. Changes in the nematode community structure, as exhibited by diversity indices, may be a reflection of real differences in the soil characteristics and changes in ecosystem functions

<i>Pochonia chlamydosporia</i> isolates used.

1<p>The source location indicates a root-knot nematode host <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035657#pone.0035657-Bourne2" target="_blank">[61]</a>.</p>2<p>A P. <i>chlamydosporia</i> var. <i>catenulata</i> strain.</p

The effect of ammonium chloride on VCP1 enzyme and mRNA production.

<p>Different isolates of <i>P. chlamydosporia</i> were grown in P buffer with or without 200 mM ammonium chloride (N). Error bars denote standard errors of the biological replicates. In <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035657#pone-0035657-g003" target="_blank">Fig. 3</a>a, * denotes that the mean value for P+N is significantly different (p<0.05) from the corresponding P mean; in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035657#pone-0035657-g003" target="_blank">Fig. 3</a>b all of the P+N means are significantly different from their corresponding P mean (p<0.05) except for that of Pc392 at 24h.</p

The effect of glucose and <i>M. incognita</i> eggs on VCP1 enzyme and mRNA production.

<p>Different isolates of <i>P. chlamydosporia</i> were grown in 0.01M potassium phosphate buffer pH 6.8 (P) with or without 2% glucose (G) and eggs (E, 1egg/µl). The effect of eggs was not tested on Pc147 and Pc392. Error bars denote standard errors of 3 biological replicates. In <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035657#pone-0035657-g002" target="_blank">Fig. 2</a>a, * denotes where the P+G and P+G+E means were significantly different (p<0.05) from the corresponding P mean; in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035657#pone-0035657-g002" target="_blank">Fig. 2</a>b all of the P+G and P+G+E means were significantly different from their corresponding P mean (p<0.05). In <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035657#pone-0035657-g002" target="_blank">Fig. 2</a>b, † indicates where the P+G+E mean was significantly different (p<0.05) from the P+G mean. In <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035657#pone-0035657-g002" target="_blank">Fig. 2</a>a none of the P+G+E means was significantly different from the corresponding P+G mean.</p

Primers and probes used.

<p>Primers and probes used.</p