Biochemical attributes of Indian mustard (Brassica juncea) and rapeseed (B. napus) as influenced by salicylic acid and benzothiadiazole

A field experiment was conducted during 2011-12 at Punjab Agricultural University, Ludhiana, India to assess the effect of foliar application of elicitors viz., salicylic acid (SA) and benzothiadiazole (BTH) on biochemical constituents of Brassica seeds. Seeds of Brassica juncea and B. napus were sown in the field during rabi season. Four different treatments of elicitors along with a fungicide and control were given to 10 week old plants up to four consecutive weeks. After harvesting, the seeds were analyzed for oil, total soluble protein and glucosinolate content. Results indicated that the elicitor treatments increased the oil, total soluble protein and glucosinolate content in seeds of both the Brassica species. In B. juncea, BTH (7 ppm) + SA (17 ppm) showed 12.5% higher oil content than control. In B. napus, the combinations of elicitors viz., BTH (3 ppm) + SA (33 ppm) and BTH (7 ppm) + SA (17 ppm) exhibited 15% increase in oil content compared to control. Treatment containing BTH (3 ppm) + SA (33 ppm) showed 18.72 and 15.86% higher total soluble protein content in B. juncea and B. napus seeds, respectively compared to control. In B. juncea, BTH (3 ppm) + SA (33 ppm) exhibited 7.13% higher glucosinolate content compared to control. In B. napus, BTH (7 ppm) + SA (17 ppm) showed 11.23% higher glucosinolate content than control. In conclusion, the application of elicitors, i.e., SA and BTH could be a useful tool for improving the nutritive value of B. juncea and B. napus seeds

Genome specific microsatellites in wild crucifers: Cross species/genera transferability

80-90A high degree of colinearity is now known to exist between closely related species in Brassicaceae, which theoretically allows the exchange of markers between them. Objective of this study was to explore the transferability of simple sequence repeat (SSR) primer pairs identified in crop Brassicas to related wild crucifers. Here, we report and validate transferability of 92, 67 and 105 SSR primer pairs, identified in three diploid Brassica genomes, to Brassica fruticulosa, Erucastrum abyssinicum and Diplotaxis tennuisiliquae with respective amplification of 259, 141 and 291 alleles. One thousand six hundred and thirty three (394 in RL 1359, 451 in PBR 210, 402 in RLC 1 and 386 in UP) alleles were detected in cultivated species. In cultivated Brassica species, the average number of alleles amplified were 3.31, 2.19, 2.97 whereas in wild species the values recorded were 2.70, 1.67, 2.32 for A, B and C genome SSR markers, respectively, however respective average allele values per germplasm set were 2.82 (cultivated) and 2.23 (wild). The average polymorphism information content (PIC) values of A genome primer pairs in wild species was 0.77, ranging from 0.32 to 0.94. These transferable markers can now be exploited for further genetic and introgressive breeding studies. The transferability success generally decreased as the evolutionary distance between the source and target species increased

Development and characterization of <it>Brassica juncea – fruticulosa</it> introgression lines exhibiting resistance to mustard aphid (<it>Lipaphis erysimi</it> Kalt)

<p>Abstract</p> <p>Background</p> <p>Mustard aphid is a major pest of <it>Brassica</it> oilseeds. No source for aphid resistance is presently available in <it>Brassica juncea</it> . A wild crucifer, <it>Brassica fruticulosa</it> is known to be resistant to mustard aphid. An artificially synthesized amphiploid, AD-4 (<it>B. fruticulosa × B. rapa</it> var. brown <it>sarson</it>) was developed for use as a bridge species to transfer <it>fruticulosa</it> resistance to <it>B. juncea</it>. Using the selfed backcross we could select a large number of lines with resistance to mustard aphid. This paper reports cytogenetic stability of introgression lines, molecular evidence for alien introgression and their reaction to mustard aphid infestation.</p> <p>Results</p> <p>Majority of introgression lines had expected euploid chromosome number(2n= 36), showed normal meiosis and high pollen grain fertility. Well-distributed and transferable simple-sequence repeats (SSR) markers for all the 18 <it>B. juncea</it> chromosomes helped to characterize introgression events. Average proportions of recipient and donor genome in the substitution lines were 49.72 and 35.06%, respectively. Minimum alien parent genome presence (27.29%) was observed in the introgression line, Ad3K-280 . Introgressed genotypes also varied for their resistance responses to mustard aphid infestations under artificial release conditions for two continuous seasons. Some of the test genotypes showed consistent resistant reaction.</p> <p>Conclusions</p> <p><it>B.juncea</it>-<it>fruticulosa</it> introgression set may prove to be a very powerful breeding tool for aphid resistance related QTL/gene discovery and fine mapping of the desired genes/QTLs to facilitate marker assisted transfer of identified gene(s) for mustard aphid resistance in the background of commercial mustard genotypes.</p

Image_1_Genome wide association studies for acid phosphatase activity at varying phosphorous levels in Brassica juncea L.tiff

Acid phosphatases (Apases) are an important group of enzymes that hydrolyze soil and plant phosphoesters and anhydrides to release Pi (inorganic phosphate) for plant acquisition. Their activity is strongly correlated to the phosphorus use efficiency (PUE) of plants. Indian mustard (Brassica juncea L. Czern & Coss) is a major oilseed crop that also provides protein for the animal feed industry. It exhibits low PUE. Understanding the genetics of PUE and its component traits, especially Apase activity, will help to reduce Pi fertilizer application in the crop. In the present study, we evaluated 280 genotypes of the diversity fixed foundation set of Indian mustard for Apase activity in the root (RApase) and leaf (LApase) tissues at three- low (5µM), normal (250µM) and high (1mM) Pi levels in a hydroponic system. Substantial effects of genotype and Pi level were observed for Apase activity in both tissues of the evaluated lines. Low Pi stress induced higher mean RApase and LApase activities. However, mean LApase activity was relatively more than mean RApase at all three Pi levels. JM06016, IM70 and Kranti were identified as promising genotypes with higher LApase activity and increased R/S at low Pi. Genome-wide association study revealed 10 and 4 genomic regions associated with RApase and LApase, respectively. Annotation of genomic regions in the vicinity of peak associated SNPs allowed prediction of 15 candidates, including genes encoding different family members of the acid phosphatase such as PAP10 (purple acid phosphatase 10), PAP16, PNP (polynucleotide phosphorylase) and AT5G51260 (HAD superfamily gene, subfamily IIIB acid phosphatase) genes. Our studies provide an understanding of molecular mechanism of the Apase response of B. juncea at varying Pi levels. The identified SNPs and candidate genes will support marker-assisted breeding program for improving PUE in Indian mustard. This will redeem the crop with enhanced productivity under restricted Pi reserves and degrading agro-environments.</p

Table_1_Genome wide association studies for acid phosphatase activity at varying phosphorous levels in Brassica juncea L.xlsx

Acid phosphatases (Apases) are an important group of enzymes that hydrolyze soil and plant phosphoesters and anhydrides to release Pi (inorganic phosphate) for plant acquisition. Their activity is strongly correlated to the phosphorus use efficiency (PUE) of plants. Indian mustard (Brassica juncea L. Czern & Coss) is a major oilseed crop that also provides protein for the animal feed industry. It exhibits low PUE. Understanding the genetics of PUE and its component traits, especially Apase activity, will help to reduce Pi fertilizer application in the crop. In the present study, we evaluated 280 genotypes of the diversity fixed foundation set of Indian mustard for Apase activity in the root (RApase) and leaf (LApase) tissues at three- low (5µM), normal (250µM) and high (1mM) Pi levels in a hydroponic system. Substantial effects of genotype and Pi level were observed for Apase activity in both tissues of the evaluated lines. Low Pi stress induced higher mean RApase and LApase activities. However, mean LApase activity was relatively more than mean RApase at all three Pi levels. JM06016, IM70 and Kranti were identified as promising genotypes with higher LApase activity and increased R/S at low Pi. Genome-wide association study revealed 10 and 4 genomic regions associated with RApase and LApase, respectively. Annotation of genomic regions in the vicinity of peak associated SNPs allowed prediction of 15 candidates, including genes encoding different family members of the acid phosphatase such as PAP10 (purple acid phosphatase 10), PAP16, PNP (polynucleotide phosphorylase) and AT5G51260 (HAD superfamily gene, subfamily IIIB acid phosphatase) genes. Our studies provide an understanding of molecular mechanism of the Apase response of B. juncea at varying Pi levels. The identified SNPs and candidate genes will support marker-assisted breeding program for improving PUE in Indian mustard. This will redeem the crop with enhanced productivity under restricted Pi reserves and degrading agro-environments.</p