Physiological Basis of Rust Resistance in French Bean ( Phaseolus vulgaris )

B. Divya<sup>1</sup>; T.S. Aghora<sup>2</sup>; N. Mohan<sup>2</sup>; A. Rekha<sup>2</sup>

Physiological Basis of Rust Resistance in French Bean (Phaseolus vulgaris)

B. Divya¹

, T.S. Aghora²

, N. Mohan²

, A. Rekha²

1. University of Horticultural Sciences, PG Center, Bengaluru-560065, India
2. Indian Institute of Horticultural Research, Bengaluru- 560 089, India

Author

Correspondence author
International Journal of Horticulture, 2014, Vol. 4, No. 11 doi: 10.5376/ijh.2014.04.0011
Received: 14 Apr., 2014 Accepted: 21 Apr., 2014 Published: 13 May, 2014

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Preferred citation for this article:

Divya et al., 2014, Physiological Basis of Rust Resistance in French Bean (Phaseolus Vulgaris), International Journal of Horticulture, 2014, Vol.4, No.11 53-57 (doi: 10.5376/ijh.2014.04.0011)

Abstract

Two resistant parents Arka Anoop and IC-525236 , three susceptible parents IIHRPB-1, IIHRPB-2 and IIHRPB-7 and six crosses IIHRPB-1×Arka Anoop, IIHRPB-2×Arka Anoop, IIHRPB-7×Arka Anoop, IIHRPB-1×IC-525236, IIHRPB-2×IC-525236 and IIHRPB-7×IC-525236 were screened for rust resistance under artificial epiphytotic conditions at Indian Institute of Horticultural Research, Bengaluru, during rabi, 2012. Studies were made on the resistant components viz., Stomata count both on upper and lower surface, Stomatal size (length and breadth), and stomatal pore size. Among the genotypes screened against rust under natural and artificial epiphytotic conditions, all the resistant parents and crosses did not show disease symptom and had less no. of stomata, small stomatal and narrow stomatal pore than all three susceptible parents which showed disease severity. The results indicated that the physiological basis of resistance, the structural features of stomata, like small stomatal pore size, narrow stoma and reduced number of stomata are highly related to impart rust resistance in french bean cultivars.

Keywords

French bean; Rust resistance; Physiological basis of resistance

French beans vary in their susceptibility to bean rust (1). The earlier studies on the genetics of rust resistance in beans have suggested that the most rust resistance was monogenic (2). Variation in pathogenicity was also found and as many as 150 races of the pathogen have been reported. As the pathogen has wide variability, it can adapt to new bean cultivar with monogenic resistance (3). Hence, the attention is shifted to partial resistance in overcoming the disease epidemics. Partial resistance is a type of resistance, which can be expressed at different phases during the life cycle of pathogen. Hence, experiment was carried out in bean rust pathosystem to find out the physiological components of resistance to rust in french bean like stomatal size and stomatal pore size.

Results

Stomata count (no.) on upper surface

Among the parents the maximum number of stomata on upper surface found to be in IIHRPB-7 (17.11) followed by IIHRPB-1 (15.33), however, the minimum number of stomata on upper surface was found in IC-525236 (11.50) followed by Arka Anoop (11.56). Whereas in F₁ combination maximum number of stomata on upper surface was found to be in IIHRPB-2×IC-525236 (12.33) and IIHRPB-1×Arka Anoop (12.33) followed by IIHRPB-7×IC-525236 (11.89) and minimum noticed in IIHRPB-7×Arka Anoop (11.33) followed by IIHRPB-2×Arka Anoop (11.56) (Table 1).

Table 1 Mean performance of parents and F₁’s for physiological components of rust resistance

Stomatal count (no.) on lower surface

The number of stomata on lower surface among the parents was found maximum in IIHRPB-2 (63.33) followed by IIHRPB-1 (62.67), however, the minimum number of stomata on lower surface was found in Arka Anoop (38.56) followed by IC-525236 (41.00).Whereas in F₁ combination maximum number of stomata on lower surface was found to be in IIHRPB-7×IC-525236 (41.40) followed by and IIHRPB-2×Arka Anoop (39.67) and minimum noticed in IIHRPB-1×Arka Anoop (36.44) followed by IIHRPB-7×Arka Anoop (36.56) (Table 1).

Stomatal Length (µm)

The maximum stomatal length was found in IIHRPB-2 (0.035) followed by IIHRPB-7 (0.033) among the parents, however, the minimum stomatal length was in Arka Anoop (0.021) followed by IC-525236 (0.022). Whereas, in F₁combination maximum length of stomata was found to be in IIHRPB-2×IC-525236 (0.025) followed by and IIHRPB-1×Arka Anoop (0.024) and minimum was noticed in IIHRPB-2×Arka Anoop (0.021) followed by IIHRPB-7×IC-525236 (0.022) (Table 1; Figure 1).

Figure 1 Mean performance of parents and F₁’s for stomatal size (µm)

Stomatal Width (µm)

Among the parents, stomatal width was maximum in IIHRPB-1 (0.022) followed by IIHRPB-2 (0.021), however, the minimum stomatal width was found in Arka Anoop (0.080) followed by IC-525236 (0.090). Whereas, in F₁ combination maximum stomatal width was in IIHRPB-7×IC-525236 (0.013) and minimum was noticed in remaining five combinations (0.009) (Table 1; Figure 1).

Stomatal Pore Length (µm)

The stomatal pore length was maximum in IIHRPB-1 (0.060) followed by IIHRPB-2 (0.050), however, the minimum stomatal pore length was found in Arka Anoop (0.013) followed by IC-525236 (0.016) among the parents. Whereas, in F₁ combination maximum stomatal pore length was found in IIHRPB-2×Arka Anoop (0.017) followed by IIHRPB-1×IIHR31 (0.016) and IIHRPB-7×IC-525236 (0.016) minimum noticed in IIHRPB-1×Arka Anoop (0.012) followed by IIHRPB-7×Arka Anoop (0.014) (Table1).

Stomatal Pore Width (µm)

The stomatal pore width found to be maximum in IIHRPB-1 (0.018) followed by IIHRPB-2 (0.016). Among the parents, however, the minimum stomatal pore width was found in Arka Anoop (0.001) followed by IC-525236 (0.002). Whereas in F₁ combination maximum stomatal pore width was found in IIHRPB-7×IC-525236 (0.005) followed by IIHRPB-1× IIHR31 (0.004), IIHRPB-2×IC-525236 (0.004) and IIHRPB-7×Arka Anoop (0.004) and minimum noticed in IIHRPB-1×Arka Anoop (0.003) and IIHRPB-2× Arka Anoop (0.003) (Table1).

Association of physiological components with PDI

Highly significant and positive correlations were observed between physiological components with PDI. Correlation coefficients ranged between 0.918 to 0.997 for stomatal characters and disease severity. Similar correlation coefficients were recorded for rate of infection and AUDPC with stomatal components (r= 0.800 to 0.978 for rate of infection and r=0.932-0.997 for AUDPC) (Table 2~Table 4; Figure 2).

Table 2 Correlation coefficient (r) estimates between PDI at different physiological growth stages and various physiological components of rust resistance

Table 3 Correlation coefficient (r) estimates between rate of infection at different physiological growth stages with various physiological components of rust resistance

Table 4 Correlation coefficient estimates between various physiological components of rust resistance with AUDPC and contingency analysis

Figure 2 Correlation coefficient estimates between various physiological components of rust resistance with AUDPC and contingency analysis

X² contingency results indicated the existence of association of physiological components with AUDPC, among the significant components, the level of significance was higher for stomatal count (upper and lower), stomatal size (length and width) and stomatal pore size (length and width).

Discussion

The studies on number of stomata in resistant and susceptible parents and F₁ have revealed significant difference. However, parents IC-525236 and Arka Anoop had considerably lower number of stomata both on upper surface (11.50~11.56) and lower surface (38.00~41.00). While susceptible parents recorded fairly higher number of stomata on both surfaces i.e., upper (15.20~17.10) and lower (59.30~63.30). As Uromyces phaseoli enters through the stomata, it was possible to infer that the lower stomata number in resistant lines had limited the infection. All F₁’s showed stoma number ranging between (11.33 to 12.33 upper surface) and (36.44 to 41.40 lower surface) which was more or less similar to that of resistant parents. Unlikely, that the stomata number alone could account for the difference in rust resistance among the genotypes. Possibly structural features of stomata might be involved in triggering appresorium formation. These observations and inference were similar to the findings of Groth and Urs (1982), Shaik (1985), Edington et al.(1994a) and Aghora (1999).

In the view of above reports, stomatal structural aspects in relation to resistance were studied. Stomatal length was maximum in susceptible parents ranging 0.031 µm to 0.035 µm. while resistant parents and hybrids recorded stomatal length of 0.021 µm to 0.025 µm which was considerably shorter. Even in case of stomatal width, the susceptible parents had wider stomata (0.018 µm to 0.022 µm) when compared to resistant parents and hybrids (0.008 µm to 0.013 µm). The stomatal pore length was found be to short in resistant parents and hybrids (0.013 µm to 0.017 µm) conversely, lengthy stomatal pore was recorded in susceptible genotypes (0.049 µm to 0.060 µm). Similar trend was observed for stomatal pore width also. Thus, broader pore size was recorded in susceptible genotypes ranging between 0.011 µm to 0.018 µm and very thin pores were found in resistant and F₁’s (0.001 µm to 0.006 µm).

The X² value indicated that association existed between all the physiological traits studied with AUDPC and the correlation coefficient confirmed the findings that the positive association existed and it was highly significant. High positive significant association was observed between AUDPC and upper stomatal number (0.9330), lower stomatal number (0.9840), stomatal length (0.9320), stomatal width (0.9680), stomatal pore length (0.9970) and pore width (0.9630). The results further confirmed that lesser stomata, small size stomata and stomatal pore play a vital role in restricting the entry of pathogen. These results were in conformity with the works of Groth and Urs (1982), Shaik (1985), Edington et al.(1994a) and Aghora (1999).

Similar to the association of AUDPC with the various physiological traits imparting resistance, PDI and rate of infection also having association with all components. Correlation analysis indicated that PDI and rate of infection had positive and highly significant association with all components, further confirmed the role of lesser stomata, small size stomata and stomatal pore size in imparting resistance. These results were in conformity with the works of Groth and Urs (1982), Shaik (1985), Edington et al. (1994a) and Aghora (1999).

Conclusion

Among the genotypes screened against rust under natural and artificial epiphytotic conditions, all the resistant parents and crosses did not show disease symptom and all three susceptible parents showed disease severity. The results indicated that the physiological basis of resistance, the structural features of stomata, like small stomatal pore size, narrow stoma and reduced number of stomata are highly related to impart rust resistance in french bean cultivars.

Materials and Methods

Material for present study consisted of five parents and six F₁combinations of the crosses, IIHRPB-1 ? IC-525236, IIHRPB-2X IC-525236 and IIHRPB-7× IC-525236 and IIHRPB-1×Arka Anoop, IIHRPB-2X Arka Anoop, and IIHRPB-7×Arka Anoop which were laid out in randomized block design with three replications. Experiment was done at experimental block of Division of Vegetable Crops, IIHR during October, 2012.

The leaves of all five parents and their F₁’s viz., IIHRPB-1×IC-525236 , IIHRPB-2×IC-525236 and IIHRPB-7×IC-525236 and×IIHRPB-1×Arka Anoop, IIHRPB-2×Arka Anoop, and IIHRPB-7×Arka Anoop at flowering stage were used for the studies.

Stomata count:

Fevicol method was employed to record mean stomata number. Fevicol was smeared on both the surfaces of leaf to form a thin film. After five minutes fevicol layer was peeled off and mounted on clean slide and observed under microscope. Number of stomata for lower surface was recorded at 10×40 magnifications and expressed in terms of number of stomata per 0.009 sq µm area of leaf surface.

Stomatal size:

The slides prepared for stomata count were observed to measure the stomata length, width, stomatal pore size (length and width) by using ocular and stage micrometer and expressed in micro meter.

Authors' contributions

BD: Participated in carrying out the entire work as M. Sc research program; TSA: Participated in the designing of the study and acted as chairperson to carry out the work under his guide lines; AR: Helped in conducting experiment on physiological resistance to rust in French bean; HPS: Helped to draft the manuscript and participated in the sequence alignment; BNR: Helped to draft the manuscript and participated in the sequence alignment

References

Aghora T.S., 1999. Studies on mechanisms of resistance to rust and genetics of quantitative characters in snap bean (Phaseolus vulgaris L.). Ph.D. Thesis, University of Agricultural Sciences, Dharwad, India

Beebe S.E., and Corrales M.P., 1991. Breeding for disease resistance. In: Van Schoon hoven, A. and Voysest, O. (eds.) Common Beans: Research for Crop Improvement. CAB International, U.K., pp. 561-617

Coyne D.P. and Schuster M.L., 1975, Genetic and breeding strategy for resistance to rust (Uromyces phaseoli Reben Wint.) in beans (Phaseolus vulgaris L.), Euphytica,24: 795-803

Edington B.R., Shanahan P.E. and Rijkenberg F.H.J., 1994a, Breeding for partial resistance in dry beans (Phaseolus vulgaris L.) to bean rust (Uromyces appendiculatus), Ann. Appl. Biol., 124: 341–350
http://dx.doi.org/10.1111/j.1744-7348.1994.tb04138.x

Groth J.V. and Urs N.V.R.R., 1982, Differences among bean cultivars in receptivity to Uromyces phaseoli var. typica. Phytopathology, 72: 374-378
http://dx.doi.org/10.1094/Phyto-72-374

Parlevliet J.E., 1981, Race non-specific resistance. In: Jenkyn, J. F. and Plumb, R. T. (eds.). Strategies for the control of Cereals Disease, Blackwell Scientific Publication, Oxford, pp. 47-54

Shaik M., 1985, Race non specific resistance in bean cultivar to races of Uromyces appendiculatus var. appendiculatus and its correlation with leaf epidermal characters, Phytopathology,75: 479-481
http://dx.doi.org/10.1094/Phyto-75-478

Yuebin, 1995, Preliminary studies on kidney bean rust resistant breeding, Acta Horticulture, 402: 115-119

International Journal of Horticulture

• Volume 4

View Options
. PDF(547KB)
. FPDF(win)
. HTML
. Online fPDF
Associated material
. Readers' comments
Other articles by authors
. B. Divya

. T.S. Aghora

. N. Mohan

. A. Rekha